Stephen S Johnston

Truven Health Analytics, Ann Arbor, Michigan, United States

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Publications (80)239.71 Total impact

  • Value in Health 05/2015; 18(3):A180. DOI:10.1016/j.jval.2015.03.1044
  • Value in Health 05/2015; 18(3):A64. DOI:10.1016/j.jval.2015.03.374
  • Value in Health 05/2015; 18(3):A58. DOI:10.1016/j.jval.2015.03.338
  • Value in Health 05/2015; 18(3):A10. DOI:10.1016/j.jval.2015.03.067
  • Value in Health 05/2015; 18(3):A8. DOI:10.1016/j.jval.2015.03.054
  • Diabetologie und Stoffwechsel 04/2015; 10(S 01). DOI:10.1055/s-0035-1549603
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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.
    Journal of Medical Economics 04/2015; DOI:10.3111/13696998.2015.1039539
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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).
    Drugs - Real World Outcomes 03/2015; 2(1). DOI:10.1007/s40801-015-0018-5
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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 P P P P P Conclusions US adults with T2DM who initiated DPP-4i therapy, particularly saxagliptin, had significantly better adherence and persistence compared with patients who initiated SUs or TZDs.
    Advances in Therapy 12/2014; 31. DOI:10.1007/s12325-014-0171-3
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    ABSTRACT: 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). 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. <80%, and at ≥90% vs. <90%). Multivariable logistic regressions compared adherence between the GLP-1RAs, adjusting for potential confounders. Sensitivity analyses were performed separating liraglutide by dose (1.2 mg/1.8 mg). Study sample included 4,041 exenatide QW, 4,586 exenatide BID, and 14,211 liraglutide (6,641 1.2 mg, 7,570 1.8 mg) patients. Median unadjusted PDC values were 0.783 for exenatide QW, 0.500 exenatide BID, 0.722 liraglutide, 0.761 liraglutide 1.2 mg, and 0.683 liraglutide 1.8 mg. Compared with patients treated with either exenatide BID or liraglutide, patients treated with exenatide QW had a statistically significantly greater multivariable-adjusted odds of achieving adherence of ≥80% (odds ratio vs. exenatide QW (OR) = 0.41 for exenatide BID; 0.80, liraglutide; 0.87, liraglutide 1.2 mg; 0.75, liraglutide 1.8 mg) and ≥90% (OR = 0.31 for exenatide BID; 0.60 liraglutide; 0.66 liraglutide 1.2 mg; 0.56 liraglutide 1.8 mg) (all P < 0.001). Patients initiating exenatide QW had significantly higher adjusted odds of adherence compared with patients initiating other GLP-1RAs. Given differences in adherence across the GLP-1RAs, research correlating these factors with clinical and economic outcomes is warranted.
    Advances in Therapy 11/2014; DOI:10.1007/s12325-014-0166-0
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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.
    Journal of the International AIDS Society 11/2014; 17(4 Suppl 3):19538. DOI:10.7448/IAS.17.4.19538
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    ABSTRACT: Background: The aim of this study was to compare the incidence rate of suicidality and suicide attempt among patients initiating efavirenz (EFV)-containing versus EFV-free antiretroviral (ARV) regimens, adjusting for confounding factors. Methods: This was a cohort analysis using administrative claims data from a US commercial and a public insurance database (Medicaid) spanning 2006-2013. We identified ARV-naive patients age ≥12 years initiating an EFV-containing or EFV-free regimen with ≥6 months of continuous enrollment prior to ARV initiation. Suicidality was defined as ICD-9-CM diagnosis (Dx) codes for suicidal ideation or attempt. Suicide attempt was defined as 1) an inpatient or emergency department claim with a Dx code for suicide attempt and 2) an expanded definition that also included Dx codes for injuries consistent with suicide attempt + a psychiatric Dx during the same encounter. The outcomes were identified from ARV initiation until the earliest of the end of exposure, enrollment or the study period. Outcomes were compared using hazard ratios (HRs) from a propensity score (PS) adjusted Cox model accounting for baseline demographics, comorbidities and comedications. Results: There were 19,983 patients (EFV: 11,187, EFV-free: 8,796) in the commercial database; 83% male and mean age 40. In the Medicaid database, there were 5,154 patients (EFV: 2,224, EFV-free: 2,930); 53% male and mean age 41. In both databases, patients initiating an EFV-free regimen had a higher prevalence of depression and other psychiatric conditions. Incidence rates for all outcomes were higher in the Medicaid population. In adjusted analyses, EFV use was not associated with suicidality or the expanded definition of suicide attempt (figures). For the restrictive definition, the point estimate was in the opposite direction in the commercial vs. the Medicaid database, which may be reflective of the patient populations and the small number of events. Conclusion: In this analysis of two large real world databases, HIV patients with depression and psychiatric conditions were less likely to be prescribed EFV. Despite PS-adjustment, we did not find conclusive evidence of an increased risk of suicidality or suicide attempt among patients initiating an EFV-containing regimen.
    IDWeek 2014 Meeting of the Infectious Diseases Society of America; 10/2014
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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.
    Journal of bone and mineral research: the official journal of the American Society for Bone and Mineral Research 09/2014; 29(9). DOI:10.1002/jbmr.2202
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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.
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    ABSTRACT: Background: Atypical antipsychotics (AA) differ from one another in their adverse event (AE) profiles. Patient-specific pre-existing risk factors for AEs, including comorbidities and concomitant medications, may render the use of certain AAs potentially inappropriate, and others relatively safer or more tolerable. Objective: To quantify the prevalence of pre-existing risk factors for AEs and potential drug-drug interactions (DDIs) associated with AA treatment among patients with schizophrenia (SCZ), bipolar disorder (BD), or major depressive disorder (MDD) newly-initiating AA treatment. Methods: Retrospective, observational study using US claims databases. Patients identified had newly-initiated on a single AA (1/1/2010-11/30/2011; index date), were aged 18-64 years, had insurance enrolment for 12 months pre- (baseline) and 1 month post-index, and had ≥1 medical claim with an ICD-9-CM diagnosis of SCZ, BD, or MDD during baseline. A comprehensive list of AE risk factors, including potential DDIs, was developed based on AA package inserts. Administrative claims-based identification algorithms flagged the presence of each medical risk factor during baseline and identified concomitant prescribing of medications (90 days pre- to 30 days post-index) potentially causing DDIs with AAs. Results: Of 97,010 patients identified, mean age was 41.2 years and 66.7% were female. Among patients initiating AA treatment, prevalence of pre-existing AE risk factors were aripiprazole 32.2%; olanzapine 51.6%; ziprasidone 75.6%; quetiapine 77.4%; risperidone 82.5%. Conclusions: Despite the availability of several AAs to treat psychiatric conditions, pre-existing AE risk factors can limit patient treatment options. Given inter-AA variability in risk factors, open access to AA may help to optimize appropriate prescribing.
    Current Drug Safety 06/2014; DOI:10.2174/1574886309666140601211551
  • Value in Health 05/2014; 17(3):A244. DOI:10.1016/j.jval.2014.03.1425
  • Value in Health 05/2014; 17(3):A285. DOI:10.1016/j.jval.2014.03.1661
  • Value in Health 05/2014; 17(3):A261-A262. DOI:10.1016/j.jval.2014.03.1522
  • Value in Health 05/2014; 17(3):A44. DOI:10.1016/j.jval.2014.03.263
  • Value in Health 05/2014; 17(3):A253-A254. DOI:10.1016/j.jval.2014.03.1477

Publication Stats

462 Citations
239.71 Total Impact Points

Institutions

  • 2013–2015
    • Truven Health Analytics
      Ann Arbor, Michigan, United States
  • 2010–2013
    • Bristol-Myers Squibb
      New York City, New York, United States
    • Northwestern University
      • Division of Cardiology (Dept. of Medicine)
      Evanston, Illinois, United States
    • MedImmune, LLC
      Maryland, United States
  • 2008–2013
    • Thomson Reuters
      New York, New York, United States
  • 2011
    • University of California, Irvine
      • Department of Medicine
      Irvine, CA, United States