Stephen S Johnston

Truven Health Analytics, Ann Arbor, Michigan, United States

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Publications (42)140.33 Total impact

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    ABSTRACT: Objective: To examine, among patients with type 2 diabetes, the association between hospitalization for heart failure (hHF) and treatment with dipeptidyl peptidase-4 inhibitors (DPP-4is) versus sulfonylureas (SUs), and treatment with saxagliptin versus sitagliptin. Research design and methods: This was a retrospective, observational study using a U.S. insurance claims database. Patients initiated treatment between 1 August 2010 and 30 August 2013, and had no use of the comparator treatments in the prior 12 months (baseline). Each comparison consisted of patients matched 1:1 on a propensity score. Time to each outcome was compared between matched groups using Cox models. Analyses were stratified by the presence of baseline cardiovascular disease (CVD). Secondary analyses examined associations between comparator treatments and other selected cardiovascular events. Results: After matching, the study included 218,556 patients in comparisons of DPP-4i and SU, and 112,888 in comparisons of saxagliptin and sitagliptin. The hazard ratios (HRs) of hHF were as follows: DPP-4i versus SU (reference): HR 0.95 (95% CI 0.78-1.15), P = 0.580 for patients with baseline CVD; HR 0.59 (95% CI 0.38-0.89), P = 0.013 for patients without baseline CVD; saxagliptin versus sitagliptin (reference): HR 0.95 (95% CI 0.70-1.28), P = 0.712 for patients with baseline CVD; HR 0.99 (95% CI 0.56-1.75), P = 0.972 for patients without baseline CVD. Comparisons of the individual secondary and composite cardiovascular outcomes followed a similar pattern. Conclusions: In patients with type 2 diabetes, there was no association between hHF, or other selected cardiovascular outcomes, and treatment with a DPP-4i relative to SU or treatment with saxagliptin relative to sitagliptin.
    No preview · Article · Jan 2016 · Diabetes care

  • No preview · Article · Jan 2016 · Medicine
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    ABSTRACT: Objectives: Atazanavir (ATV) and darunavir (DRV) are protease inhibitors approved for HIV treatment in combination with ritonavir (/r). The objectives of this study were to compare persistence (time to treatment discontinuation/modification), adherence, and healthcare costs among patients with HIV initiating ATV/r or DRV/r. Methods: This retrospective cohort study used commercial and Medicaid administrative insurance claims data. Patients initiating ATV/r or DRV/r from 2006-2013 with continuous enrollment for ≥6 months before and ≥3 months after initiation were included. Patients were followed from initiation until discontinuation/modification (≥30 day gap in ATV or DRV or initiation of a new antiretroviral medication), during which time adherence (proportion of days covered [PDC], with PDC≥80% or 95% considered adherent) and per-patient per-month (PPPM) total healthcare costs were measured. DRV/r patients were propensity score matched to ATV/r patients at a 1:1 ratio to achieve balance on potentially confounding demographic and clinical factors. Commercial and Medicaid samples were analyzed separately, as were antiretroviral (ART)-naïve and experienced patients. Results: The final samples comprised 2,988 commercially-insured and 1,158 Medicaid-insured patients. There were no significant differences in hazards of discontinuation/modification between the ATV/r or DRV/r cohorts. With respect to odds of being adherent, the only marginally significant result was comparing odds of achieving PDC≥80 among ART-naïve Medicaid patients, which favored ATV/r. All other adherence comparisons were not significant. Though ATV/r cohorts tended to have lower PPPM costs, the majority of these differences were not statistically significant. Conclusions: Patients with HIV treated with either ATV/r or DRV/r had similar time to treatment discontinuation/modification, adherence, and monthly healthcare costs. Results were similar across the pre-specified subgroups. These findings are useful not only as an insight into clinical practice, but also as a resource for healthcare providers and payers evaluating treatment options for HIV+ individuals.
    No preview · Article · Dec 2015 · Journal of Medical Economics
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    ABSTRACT: To quantify the cost of acute major adverse cardiac events (MACE; myocardial infarction [MI] and stroke) stratified by cardiovascular disease (CVD) risk factors in commercially, Medicare Supplemental-, and Medicaid-insured patients with type 2 diabetes mellitus (T2DM). U.S. administrative claims data were used to identify patients with T2DM aged ≥18 and continuously enrolled with insurance benefits from 7/1/2009-6/30/2010 (baseline). Patients were classified into three baseline CVD risk groups (highest, medium, and lowest) and followed from 7/1/2010 until 1 year or censoring (follow-up) to measure per-patient per-month (PPPM) all-cause healthcare costs. Multivariable regression compared costs between patients with/without MACE during follow-up. Patients with MACE were further followed for up to 1 year after initial event to quantify longitudinal event costs. Sample comprised 1,415,598 T2DM patients. Over average follow-up ranging from 301-343 days across CVD risk groups, 10,399 patients experienced MACE. Expected multivariable-adjusted mean PPPM costs of MACE per 100 covered patients within each CVD risk group varied by payer and generally increased with CVD risk (range: $1,555 in lowest-risk commercially insured patients to $18,727 in highest-risk Medicaid-insured patients). Longitudinal costs of MACE were lowest among Medicare Supplemental-insured patients with stroke ($22,657 initial event, $2,488 PPPM up-to 1-year follow-up care) and highest among Medicaid-insured patients with MI ($41,505 initial event, $4,799 PPPM up to 1-year follow-up care). These results illustrate the potential clinical and economic importance of considering patients' CVD risk and medications' cardiovascular safety profile when treating T2DM patients.
    No preview · Article · Jul 2015 · Journal of Medical Economics
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    ABSTRACT: Introduction Oral antidiabetes medications, including dipeptidyl peptidase-4 inhibitors (DPP-4is) saxagliptin and sitagliptin, are used for the treatment of type 2 diabetes (T2D). The study objective was to compare all-cause and diabetes-related costs following initiation of saxagliptin or sitagliptin. Methods Patients aged ≥18 years initiating saxagliptin or sitagliptin between January 1, 2009 and January 31, 2012 in the Truven Health MarketScan Commercial and Medicare Supplemental databases were identified. Patients were required to have continuous enrollment for ≥365 days before and ≥365 days after the index date (date of the first saxagliptin or sitagliptin claim). Additionally, patients were required to have a claim with a T2D diagnosis (ICD-9-CM 250.×0, 250.×2) and no claims for a DPP-4i medication before the index date. All-cause and diabetes-related medical costs and total costs (including pharmacy costs) were captured over the 1-year follow-up period. Generalized linear models with log link and gamma distribution were fit to compare costs between the two cohorts using cost ratios, controlling for patient baseline characteristics. Recycled prediction methods were used to generate adjusted predicted costs and confidence intervals. Results The final sample comprised 3354 saxagliptin initiators and 26,895 sitagliptin initiators. The average age of saxagliptin and sitagliptin initiators was 57 years and just over 50% were males. After adjusting for baseline characteristics, saxagliptin patients had significantly lower average all-cause medical costs (cost ratio = 0.901, P < 0.001; predicted mean costs: $8687 vs. $9646) compared with sitagliptin patients over the 1-year follow-up. Findings were consistent for diabetes-related medical costs (cost ratio = 0.890, P < 0.001; predicted mean costs: $2180 vs. $2450). Total costs were also lower for saxagliptin initiators (cost ratio = 0.950, P = 0.002; predicted mean costs: $13,911 vs. $14,651) over the 1-year follow-up period. Conclusion Initiation of treatment with saxagliptin was associated with lower medical costs over 1 year compared with initiation of sitagliptin among adults with T2D. Funding AstraZeneca.
    No preview · Article · May 2015 · Value in Health
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    ABSTRACT: To compare healthcare costs and utilization between commercially insured patients with Type 2 diabetes mellitus (T2DM) in the United States newly initiating exenatide once weekly (QW) or liraglutide. This retrospective cohort study used US administrative claims data to study patients with T2DM initiating exenatide QW or liraglutide (initiated therapy=index therapy). Patients were included if they had T2DM, were glucagon-like peptide-1 receptor agonist (GLP-1RA)-naïve, initiated exenatide QW or liraglutide from 2/1/2012-10/1/2012 (date of initiation=index), were ≥18 years at index, and had continuous enrollment for 12 months before (baseline) to 6 months after index (follow-up). Study outcomes were overall and diabetes-specific healthcare utilization and costs. Multivariable regressions compared the study outcomes between exenatide QW and liraglutide, adjusting for potential confounders. Sensitivity analyses were performed to assess liraglutide by dose (1.2 mg/1.8 mg). Study sample included 9,106 liraglutide (4,188, 1.2 mg; 4,918, 1.8 mg) patients and 2,445 exenatide QW patients. In multivariable-adjusted analyses, compared with liraglutide patients, exenatide QW patients had statistically significant lower odds of overall inpatient admissions (odds ratio [OR]=0.80, p=0.046) and diabetes-specific (OR=0.83, p=0.026) inpatient admissions, similar overall total costs ($7,833 exenatide QW, $8,296 liraglutide, p=0.069) and diabetes-specific total costs ($3,610 exenatide QW, $3,736 liraglutide, p=0.298), and statistically significantly lower overall medical costs ($3,939 exenatide QW, $4,652 liraglutide, p=0.008) and diabetes-specific medical costs ($1,161 exenatide QW, $1,469 liraglutide, p=0.007). Sensitivity analyses assessing liraglutide by dose were directionally consistent. Unadjusted exploratory analyses showed that exenatide QW patients obtained a greater median number of days supplied for their GLP-1RA during follow-up (141 days) than liraglutide patients (124 days). In this 6-month follow-up study, patients receiving exenatide QW had similar total healthcare costs but lower odds of inpatient admission and lower medical costs compared with patients receiving liraglutide.
    No preview · Article · Apr 2015 · Journal of Medical Economics
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    Stephen S. Johnston · Donna McMorrow · Amanda M. Farr · Paul Juneau · Sarika Ogale
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    ABSTRACT: Introduction While there is a substantial body of literature on the comparative healthcare costs of biologics used to treat rheumatoid arthritis (RA), nearly all of these investigations have been exclusively focused on anti-tumor necrosis factor-α (anti-TNF) agents in the setting of first-line biologic treatment. This study compared healthcare costs between RA patients treated with infused biologics after previously using at least one other biologic agent. Methods Using a large US administrative claims dataset, adult RA patients initiating an infused biologic (abatacept, infliximab, tocilizumab) between January 1, 2010 and January 1, 2012 (initiation = index) were identified. Rituximab was excluded because of unique dosing intervals, which make it difficult to determine treatment discontinuation using a claims database. Patients were required to have used one or more other biologic (infused or injected) at any time before index. Patients could contribute multiple observations to the dataset; one for each infused biologic they initiated between January 1, 2010 and January 1, 2012. A 6-month period before index was used to measure patient characteristics. A variable-length follow-up period after index was used to measure per-patient per-month (PPPM) healthcare costs, including biologic costs, RA-related healthcare costs, and all-cause healthcare costs. Generalized estimating equations models compared healthcare costs between the biologic agents, adjusting for patients’ demographics and clinical characteristics. Results The sample comprised 3,771 infused biologic initiations (abatacept = 1,759; infliximab = 922; tocilizumab = 1,090); the mean age of participants was 55 years, 82 % were female, and the median follow-up ranged from 251 to 280 days. Compared with other patients, patients treated with tocilizumab had significantly lower (all P Conclusions Among RA patients treated with infused biologics after previously using at least one other biologic, patients treated with tocilizumab had the lowest real-world healthcare costs, largely driven by lower costs directly related to biologic treatment. Such biologic-related cost differences may be driven by variations in real-world treatment patterns (e.g., dose, escalation, treatment frequency).
    Preview · Article · Mar 2015 · Drugs - Real World Outcomes
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    ABSTRACT: Introduction Patients with type 2 diabetes mellitus (T2DM) must remain adherent and persistent on antidiabetic medications to optimize clinical benefits. This analysis compared adherence and persistence among adults initiating dipeptidyl peptidase-4 inhibitors (DPP-4is), sulfonylureas (SUs), and thiazolidinediones (TZDs) and between patients initiating saxagliptin or sitagliptin, two DPP-4is. Methods This retrospective cohort study utilized the US MarketScan® (Truven Health Analytics, Ann Arbor, MI, USA) Commercial and Medicare Supplemental health insurance claims databases. Adults aged ≥18 years with T2DM who initiated a DPP-4i, SU, or TZD from January 1, 2009 to January 31, 2012 were included. Patients must have been continuously enrolled for ≥1 year prior to and ≥1 year following initiation. Adherence was measured using proportion of days covered (PDC), with PDC ≥ 0.80 considered adherent. Persistence was measured as time to discontinuation, defined as last day with drug prior to a 60+ days gap in therapy. Multivariable logistic regression and Cox proportional hazards models compared the outcomes between cohorts, controlling for baseline differences. Results The sample included 238,372 patients (61,399 DPP-4i, 134,961 SU, 42,012 TZD). During 1-year follow-up, 47.3% of DPP-4i initiators, 41.2% of SU initiators, and 36.7% of TZD initiators were adherent. Adjusted odds of adherence were significantly greater among DPP-4i initiators than SU (adjusted odds ratio [AOR] = 1.678, P
    Preview · Article · Dec 2014 · Advances in Therapy
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    ABSTRACT: Introduction Greater adherence to medications has been broadly demonstrated to be associated with improved clinical outcomes. However, there is limited real-world evidence on adherence to glucagon-like peptide-1 receptor agonist (GLP-1RA) therapy in patients with type 2 diabetes mellitus (T2DM). Methods This retrospective cohort study used United States administrative claims data to compare adherence to GLP-1RAs in T2DM patients initiating exenatide once weekly (QW), exenatide twice daily (BID), or once-daily liraglutide (initiated therapy = index therapy). Patients were included if they had T2DM, were GLP-1RA-naïve, initiated a GLP-1RA from 02/01/2012–01/31/2013 (date of initiation = index), were ≥18 years at index, and had continuous enrollment for 12 months before (baseline) to 6 months after index (follow-up). Study outcome was index GLP-1RA adherence (proportion of days covered [PDC] during follow-up, dichotomized at ≥80% vs.
    No preview · Article · Nov 2014 · Advances in Therapy
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    ABSTRACT: Introduction There is a lack of data comparing the protease inhibitors (PIs) atazanavir (ATV) and darunavir (DRV) in a real-world setting. This study compared persistence (time to switch/discontinuation) to therapy between ATV-treated and DRV-treated patients with human immunodeficiency virus (HIV). Materials and Methods Retrospective, observational cohort study using US insurance claims for commercially and Medicaid-insured patients. Patients were aged ≥18 years and initiated an ATV- or DRV-based regimen boosted with ritonavir between 7/1/2006 and 3/31/2013, with ≥6 months of continuous enrolment prior to and ≥3 months of continuous enrolment following initiation; patients were required to have ≥1 inpatient or outpatient medical claim with an ICD-9-CM diagnosis code for HIV during that time period of enrolment. Patients with no claims for antiretroviral therapy (ART) any time prior to initiation were considered to be ART-naïve. Time to switch/discontinuation was defined as the number of days from initiation of the regimen until earliest of: (1) a ≥30-day continuous gap in therapy in ATV or DRV; (2) a prescription claim for an ART agent that was not part of the initial regimen (with the exception of changes in concomitant nucleoside reverse transcriptase inhibitors or the addition of integrase inhibitors); (3) censoring at a ≥30-day continuous gap in therapy in ritonavir; (4) censoring at disenrolment from insurance benefits or (5) censoring at the study end date (9/30/2013 in the commercial data and 12/31/2013 in the Medicaid data). Time to switch/discontinuation was compared using incidence rates and multivariable Cox proportional hazards models adjusted for calendar time, patient demographics and clinical characteristics. Results Table 1 displays the study results and cohort sample sizes. Mean ages across the cohorts were 41–42 years. The proportions of patients who were ART-naïve were 58–59% among the ATV/r cohorts and 53–55% among the DRV/r cohorts. There were no significant differences in the adjusted hazards of switch/discontinuation between the cohorts. Conclusions The incidence of switch/discontinuation was higher among Medicaid patients (who may be socioeconomically disadvantaged) than Commercial patients. There were no significant differences in persistence (time to switch/discontinuation) with the initiated PI among HIV patients who initiated an ATV-based regimen versus a DRV-based regimen.
    Full-text · Article · Nov 2014 · Journal of the International AIDS Society
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    ABSTRACT: Hip fractures are common, morbid, costly, and associated with subsequent fractures. Historically, post-fracture osteoporosis medication use rates have been poor, but have not been recently examined in a large-scale study. We conducted a retrospective, observational cohort study based on U.S. administrative insurance claims data for beneficiaries with commercial or Medicare supplemental health insurance. Eligible participants were hospitalized for hip fracture between January 1, 2002, and December 31, 2011, and aged 50 years or older at admission. The outcome of interest was osteoporosis medication use within 12 months after discharge. Patients were censored after 12 months, loss to follow-up, or a medical claim for cancer or Paget's disease, whichever event occurred first. During the study period, 96,887 beneficiaries met inclusion criteria, with a mean age 80 years and 70% were female. A total of 34,389 (35.5%) patients were censored before reaching 12 months of follow-up. The Kaplan-Meier estimated probability of osteoporosis medication use within 12 months after discharge was 28.5%. The rates declined significantly from 40.2% in 2002, to 20.5% in 2011 (P for trend < 0.001). In multivariable Cox proportional hazards models, a number of patient characteristics were associated with reduced likelihood of osteoporosis medication use, including older age and male gender. However, the predictor most strongly and most positively associated with osteoporosis medication use after fracture was osteoporosis medication use before the fracture (Hazard Ratio = 7.45, 95% CI 7.23-7.69). Most patients suffering a hip fracture do not use osteoporosis medication in the subsequent year and treatment rates have worsened. © 2014 American Society for Bone and Mineral Research.
    Full-text · Article · Sep 2014 · Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research
  • Stephen S Johnston · Timothy Juday · Amanda M Farr · Bong-Chui Chu · Tony Hebden
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    ABSTRACT: Objectives To compare antiretroviral therapy (ART) adherence and persistence and total healthcare expenditures in Medicaid-insured patients with human immunodeficiency virus (HIV) initiating preferred or nonpreferred first-line ART based on March 2012 HHS HIV treatment guidelines. Study Design Retrospective observational study using Medicaid administrative healthcare claims from 15 states. Methods Subjects were HIV patients 18 to 64 years who initiated first-line HIV-related ART between January 1, 2007, and September 30, 2011, with continuous enrollment for 6 months prior to and at least 3 months following ART initiation. Patients were classified as having initiated preferred or nonpreferred ART based on March 2012 HHS HIV treatment guidelines. Outcomes were: ART adherence (proportion of days covered dichotomized at ≥80% and ≥95%), time to ART nonpersistence, and per patient per month (PPPM) total healthcare expenditures. Outcomes were evaluated using multivariable regressions. Results Sample included 1979 patients initiating preferred ART regimens and 1614 patients initiating nonpreferred ART; overall mean age was 41 years; 48% of subjects were female. In the multivariable analyses, patients initiating preferred ART regimens had significantly greater odds of adherence ≥80% (odds ratio [OR], 1.38; 95% CI, 1.07-1.77) and adherence ≥95% (OR, 1.26; 95% CI, 1.05-1.51), and a significantly lower hazard of nonpersistence (HR, 0.48; 95% CI, 0.44-0.52). PPPM total healthcare expenditures were numerically lower for patients initiating preferred ART regimens (-$341; 95% CI, -$888 to $255) but the difference was not deemed significant. Conclusions This study reinforces the value of HHS recommendations for first-line ART. The potential impact of these findings will grow as more HIV patients become Medicaid-eligible under the Patient Protection and Affordable Care Act.
    No preview · Article · Jun 2014 · The American journal of managed care
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    ABSTRACT: To describe the characteristics, treatment, and health care expenditures of Medicare Supplemental-insured patients with painful diabetic peripheral neuropathy (pDPN), post-herpetic neuralgia (PHN), or fibromyalgia. Retrospective cohort study. United States clinical practice, as reflected within a database comprising administrative claims from 2.3 million older adults participating in Medicare supplemental insurance programs. Selected patients were aged ≥65 years, continuously enrolled in medical and prescription benefits throughout years 2008 and 2009, and had ≥1 medical claim with an International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis code for DPN, PHN, or fibromyalgia, followed within 60 days by a medication or pain intervention procedure used in treating pDPN, PHN, or fibromyalgia during 2008-2009. Utilization of, and expenditures on, pain-related and all-cause pharmacotherapy and medical interventions in 2009. The study included 25,716 patients with pDPN (mean age 75.2 years, 51.2% female), 4,712 patients with PHN (mean age 77.7 years, 63.9% female), and 25,246 patients with fibromyalgia (mean age 74.4 years, 73.0% female). Patients typically had numerous comorbidities, and many were treated with polypharmacy. Mean annual expenditures on total pain-related health care and total all-cause health care, respectively, (in 2010 USD) were: $1,632, $24,740 for pDPN; $1,403, $16,579 for PHN; and $1,635, $18,320 for fibromyalgia. In age-stratified analyses, pain-related health care expenditures decreased as age increased. The numerous comorbidities, polypharmacy, and magnitude of expenditures in this sample of Medicare supplemental-insured patients with pDPN, PHN, or fibromyalgia underscore the complexity and importance of appropriate management of these chronic pain patients.
    No preview · Article · Jan 2014 · Pain Medicine
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    ABSTRACT: To quantify the prevalence of potential drug-drug/drug-condition interactions (DDI/DCI) among fibromyalgia patients initiating pregabalin or duloxetine, and to determine the impact of potential DDI/DCI on health care expenditures. Retrospective cohort study. U.S. clinical practice, as reflected within a large administrative claims database. Fibromyalgia patients newly initiating pregabalin or duloxetine between July 1, 2008 and October 1, 2010 (initiation date = index). Potential DDI measured using clinical software that identifies co-prescription of medications that potentially interact with pregabalin or duloxetine. Potential DCI, drawn from the contraindications and warnings and precautions sections of pregabalin and duloxetine prescribing information, measured using administrative claims-based algorithms. All-cause health care expenditures measured throughout a 6-month postindex period. Analyses included univariate, bivariate, and multivariable statistical approaches. Seven thousand seven hundred fifty-one pregabalin and 7,785 duloxetine initiators were selected for study: mean age 49 years, 88% female. Only 1.4% of pregabalin initiators had ≥1 potential pregabalin DCI; none had potential pregabalin DDI. In contrast, 67% of duloxetine initiators had potential duloxetine DDI/DCI, driven mostly by potential duloxetine DDI (62% of duloxetine initiators). Compared between pregabalin and duloxetine initiators, differences in the prevalence of potential DDI/DCI were statistically significant (P < 0.001). Multivariable analyses indicated that, among duloxetine initiators, those with potential duloxetine DDI/DCI had postinitiation health care expenditures that were $670 higher (P < 0.001) than those without potential duloxetine DDI/DCI. Among pregabalin initiators, potential pregabalin DDI/DCI were not associated with health care expenditures. Among fibromyalgia patients initiating pregabalin or duloxetine, potential duloxetine DDI could be highly prevalent. Among duloxetine initiators, potential duloxetine DDI/DCI were significantly associated with increased health care expenditures.
    No preview · Article · Jan 2014 · Pain Medicine
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    Yang Zhao · Stephen S Johnston · David M Smith · Donna McMorrow · John Krege · Kelly Krohn
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    ABSTRACT: This study examined the association between teriparatide (TPTD) adherence, and healthcare utilization and costs among hip fracture (HFx) patients. Individuals aged 50years and older with an HFx between 1/1/2002-12/31/2010 were identified from a large US administrative claims database. The first HFx date during this period was designated as the index. Selected patients had at least 6months of pre-index continuous enrollment (baseline) and no baseline TPTD use, cancer, or Paget's disease. Patients initiating TPTD post-index were followed until censoring at switch to bisphosphonates, disenrollment, 36months post-index, or diagnosis of cancer or Paget's disease. Teriparatide adherence was measured as the proportion of days covered (PDC) by TPTD prescriptions, during the follow-up period, to construct three adherence groups: low (PDC≤0.5), medium (0.5<PDC≤0.8), and high (PDC>0.8) adherence. Outcome measures were repeated HFx, number of inpatient admissions, and per-patient-per-month (PPPM) healthcare costs. Multivariable generalized linear models examined the association between the TPTD adherence groups and the outcomes, adjusting for cross-group differences in patient characteristics. A total of 824 patients (mean age 75years, 90% female) were included: 30% low, 27% medium, and 44% high adherence. In multivariable analyses, high adherence was significantly (all p<0.05) directly associated with increased PPPM pharmacy costs ($621 low, $1,093 medium, and $1,572 high), but also with the lowest inpatient ($963 low, $960 medium, and $629 high) and outpatient ($1,087 low, $1,068 medium, and $776 high) costs, leading to the highest total costs in the medium adherence group but similar costs in the high and low adherence groups ($2,599 low, $3,163 medium, and $2,869 high). The high adherence group also had the lowest number of inpatient admissions. Significantly increased pharmacy costs associated with the high TPTD adherence group were offset by significantly fewer inpatient admissions, fewer repeated HFx, and lower inpatient and outpatient costs.
    Full-text · Article · Dec 2013 · Bone
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    ABSTRACT: The frequency and financial impact of potential drug-drug interactions (DDIs) and drug-condition interactions (DCIs) in patients with painful diabetic peripheral neuropathy (DPN) treated with either pregabalin or duloxetine were compared. This retrospective cohort study was conducted using a large U.S. administrative claims database. Patients selected for study inclusion had a diagnosis of DPN and were newly initiated on either pregabalin or duloxetine between July 1, 2008, and October 1, 2010. Data on potential DDIs and DCIs were collected. Health care costs were measured as the sum of gross covered payments for all medical and prescription claims incurred during the six months after the index date. The study sample comprised 2499 pregabalin users and 1354 duloxetine users. Among pregabalin users, 48 (1.8%) had at least one potential pregabalin DCI; none had potential pregabalin DDIs. Among duloxetine users, 966 (71%) had at least one potential duloxetine DDI or DCI. The frequencies of potential DDIs and DCIs differed significantly between pregabalin and duloxetine users (p < 0.001). Potential duloxetine DDIs and DCIs were associated with a significant increase in mean health care costs in duloxetine users (p = 0.002). Potential pregabalin DDIs and DCIs were not associated with additional health care costs in pregabalin users. Among patients with painful DPN treated with either pregabalin or duloxetine, the frequency of potential duloxetine DDIs and DCIs was substantially higher than that of pregabalin. Potential DDIs and DCIs were associated with significantly increased health care costs in duloxetine users.
    No preview · Article · Dec 2013 · American journal of health-system pharmacy: AJHP: official journal of the American Society of Health-System Pharmacists
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    Stephen S Johnston · Kathleen Wilson · Alice Huang · David Smith · Helen Varker · Adam Turpcu
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    ABSTRACT: This study compared the number of, and expenditures on, first-line intravitreal anti-vascular endothelial growth factor (anti-VEGF) injections between patients who were treated with aflibercept or ranibizumab for wet age-related macular degeneration (AMD). This was a retrospective cohort study based on U.S. administrative claims data. Selected patients had initiated first-line intravitreal anti-VEGF treatment with ranibizumab or aflibercept (index date) between November 18, 2011 and April 30, 2013, were aged ≥18 years on the index date, had 12 months of continuous insurance enrollment prior to the index date (baseline period), were diagnosed with wet AMD during the baseline period or on the index date, and had at least 6 or 12 months of follow-up enrollment after the index date without switching to a different anti-VEGF agent (follow-up periods). Outcomes measured within the 6 and 12 month follow-up periods included the number of, and healthcare expenditures on, intravitreal anti-VEGF injections. Multivariable regressions compared the outcomes between aflibercept and ranibizumab. The 6 months analyses included 319 aflibercept patients and 1,054 ranibizumab patients (12 month analyses: 57 and 374, respectively). Over the first 6 months after the index date, neither the number of injections (aflibercept mean = 3.8 ± 1.6; ranibizumab mean = 3.9 ± 1.9) nor the expenditures on injections (aflibercept mean = $7 468 ± $4 211; ranibizumab mean = $7 816 ± $4 834) differed significantly between aflibercept patients and ranibizumab patients (in multivariable regression treating ranibizumab as reference: incidence rate ratio = 0.97, 95% confidence interval [CI] 0.91-1.03, P = 0.277; cost ratio = 0.96, 95% CI 0.89-1.04, P = 0.338). Differences were also insignificant in the 12 month analyses. The overall mean days between injections differed by only 1.8 (95% CI 1.3-2.3) days between the aflibercept patients and ranibizumab patients (42.4 and 40.6, respectively). Aflibercept and ranibizumab were used at a similar frequency resulting in similar intravitreal anti-VEGF injection healthcare expenditures among wet AMD patients initiating first-line intravitreal anti-VEGF treatment.
    Full-text · Article · Dec 2013 · Advances in Therapy
  • Stephen S. Johnston

    No preview · Article · Jul 2013 · Sex Transm Dis
  • Stephen S Johnston

    No preview · Article · Jul 2013 · Sexually transmitted diseases
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    ABSTRACT: This is the first study to compare the incidence and health care costs of medically attended adverse effects in atazanavir- and darunavir-based antiretroviral therapy (ART) among U.S. Medicaid patients receiving routine HIV care. This was a retrospective study using Medicaid administrative health care claims from 15 states. Subjects were HIV patients aged 18 to 64 years initiating atazanavir- or darunavir-based ART from January 1, 2003, to July 1, 2010, with continuous enrollment for 6 months before (baseline) and 6 months after (evaluation period) ART initiation and 1 or more evaluation period medical claim. Outcomes were incidence and health care costs of the following medically attended (International Classification of Diseases, Ninth Revision, Clinical Modification-coded or treated) adverse effects during the evaluation period: gastrointestinal, lipid abnormalities, diabetes/hyperglycemia, rash, and jaundice. All-cause health care costs were also determined. Patients treated with atazanavir and darunavir were propensity score matched (ratio = 3:1) by using demographic and clinical covariates. Multivariable models adjusted for covariates lacking postmatch statistical balance. Propensity-matched study sample included 1848 atazanavir- and 616 darunavir-treated patients (mean age 41 years, 50% women, 69% black). Multivariable-adjusted hazard ratios (HRs) (for darunavir, reference = atazanavir) and per-patient-per-month health care cost differences (darunavir minus atazanavir) were as follows: gastrointestinal, HR = 1.25 (P = 0.04), $43 (P = 0.13); lipid abnormalities, HR = 1.38 (P = 0.07), $3 (P = 0.88); diabetes/hyperglycemia, HR = 0.84 (P = 0.55), $13 (P = 0.69); and rash, HR = 1.11 (P = 0.23), $0 (P = 0.76); all-cause health care costs were $1086 (P<0.001). Too few instances of jaundice (11 in atazanavir and 1 in darunavir) occurred to support multivariable modeling. Medication tolerability can be critical to the success or failure of ART. Compared with darunavir-treated patients, atazanavir-treated patients had significantly fewer instances of medically attended gastrointestinal issues and more instances of jaundice and incurred significantly lower health care costs.
    Preview · Article · Mar 2013 · Value in Health

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636 Citations
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Institutions

  • 2013-2015
    • Truven Health Analytics
      Ann Arbor, Michigan, United States
  • 2008-2013
    • Thomson Reuters
      New York, New York, United States
  • 2010
    • Northwestern University
      • Division of Cardiology (Dept. of Medicine)
      Evanston, Illinois, United States