Kent H Summers

Endo Pharmaceuticals, Filadelfia, Pennsylvania, United States

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Publications (32)73.84 Total impact

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    ABSTRACT: Literature has shown that chronic pain patients prescribed opioids are at an increased risk for experiencing drug-drug interactions as a result of polypharmacy. In addition, chronic, noncancer pain patients who experience drug-drug interactions have been shown to have greater health care utilization and costs. However, no study has focused on the health economics of major clinically significant drug-drug interactions associated with long-acting opioids. To (a) estimate the prevalence of major drug-drug interactions among patients prescribed a long-acting opioid and (b) evaluate the potential impact of major drug-drug interactions on health care costs. This study was a retrospective cohort analysis using claims data from the MarketScan Commercial Claims and Encounter Database between 2008 and 2010. Patients with at least 1 prescription for a long-acting opioid for ≥ 30 days were placed into cohorts according to the expected clinical impact of the potential drug-drug interaction: major versus none. Propensity score matching was used to mitigate differences in baseline characteristics between the cohorts. Health care costs were based on payments for all covered health care services, which consisted of inpatient and outpatient medical, emergency department, and outpatient prescription costs. Among 57,752 chronic, noncancer pain patients who met all inclusion and exclusion criteria, 5.7% (3,302) were exposed to a potential major drug-drug interaction. The costs associated with a potential interaction versus no potential interaction were significantly more after baseline characteristics of the cohorts were normalized by propensity score matching. Monthly health care costs in the 90-day post-index period were significantly greater ($3,366 vs. $2,757, a $609 difference) in patients exposed to a potential drug-drug interaction of major clinical significance, compared with those not exposed to a drug-drug interaction. The higher health care costs were mainly driven by outpatient and inpatient medical costs. Exposure to potential drug-drug interactions may result in unnecessary and unintended health care costs. Physicians should be made aware of commonly administered cytochrome P450 (CYP450) metabolized drugs in the chronic pain patient and consider prescribing non-CYP450 metabolized opioid and nonopioid analgesics. Managed care's use of utilization management tools to avoid these exposures may reduce costs.
    Journal of managed care pharmacy: JMCP 05/2014; 20(5):467-76. · 2.71 Impact Factor
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    ABSTRACT: Chronic pain patients may be subject to polypharmacy because of long-term pharmacological pain treatment and additional comorbidities. Many chronic pain patients expose themselves to potential drug-drug interactions (DDIs) and these interactions can have unintended and severe consequences. Prevalence and costs associated with DDIs are inconsistent and has led to an inadequate level of awareness among the medical community; therefore, it has become necessary to re-evaluate the rates of DDIs in chronic pain patients. Utilizing medical and prescription claims databases, five studies were conducted to assess the health care utilization of and associated financial payments for patients >18 years with chronic noncancer pain. The studies evaluated drug-drug exposures with the potential to cause DDIs specifically occurring through the CYP450 enzyme system. The studies reported that drug-drug exposures are prevalent, costly and can occur in any age group and that physicians should consider ways to limit their patients' exposure to potential DDIs.
    Expert Review of Pharmacoeconomics & Outcomes Research 12/2013; 13(6):725-34. DOI:10.1586/14737167.2013.851006 · 1.67 Impact Factor
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    K Summers · J Pergolizzi · L Ma · D Foster · B Overholser · K Sowinski ·

    Value in Health 05/2013; 16(3):A12. DOI:10.1016/j.jval.2013.03.076 · 3.28 Impact Factor
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    N Furiak · R W Klein · J C Gahn · S B Camper · K Summers ·

    Value in Health 05/2013; 16(3):A62-3. DOI:10.1016/j.jval.2013.03.1589 · 3.28 Impact Factor
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    ABSTRACT: The objective of this study was to quantify the direct medical resources used and the corresponding burden of disease in the treatment of patients with schizophrenia. Because low-frequency administration (LFA) of risperidone guarantees adherence during treatment intervals and offers fewer opportunities to discontinue, adherence and persistence were assumed to improve, thereby reducing relapses of major symptoms. A decision tree model including Markov processes with monthly cycles and a five-year maximum timeframe was constructed. Costs were adapted from the literature and discounted at a 3% annual rate. The population is a demographically homogeneous cohort of patients with schizophrenia, differentiated by initial disease severity (mildly ill, moderately ill, and severely ill). Treatment parameters are estimated using published information for once-daily risperidone standard oral therapy (RIS-SOT) and once-monthly risperidone long-acting injection (RIS-LAI) with LFA therapy characteristics derived from observed study trends. One-year and five-year results are expressed as discounted direct medical costs and mean number of relapses per patient (inpatient, outpatient, total) and are estimated for LFA therapies given at three, six, and nine month intervals. The one-year results show that LFA therapy every 3 months (LFA-3) ($6,088) is less costly than either RIS-SOT ($10,721) or RIS-LAI ($9,450) with similar trends in the 5-year results. Moreover, the model predicts that LFA-3 vs. RIS-SOT vs. RIS LAI therapy will reduce costly inpatient relapses (0.16 vs. 0.51 vs. 0.41). Extending the interval to six (LFA-6) and nine (LFA-9) months resulted in further reductions in relapse and costs. Limitations include the fact that LFA therapeutic options are hypothetical and do not yet exist and limited applicability to compare one antipsychotic agent versus another as only risperidone therapy is evaluated. However, study results have quantified the potential health state improvements and potential direct medical cost savings achievable with the development and use of LFA medication delivery technologies.
    Annals of General Psychiatry 11/2012; 11(1):29. DOI:10.1186/1744-859X-11-29 · 1.40 Impact Factor
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    Sheryl L Szeinbach · Enrique Seoane-Vazquez · Kent H Summers ·
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    ABSTRACT: This study used a standard research approach to create a final conceptual model and the Preference for the Testosterone Replacement Therapy (P-TRT) instrument. A discussion guide was developed from a literature review and expert opinion to direct one-on-one interviews with participants who used testosterone replacement therapy and consented to participate in the study. Data from telephone interviews were transcribed for theme analysis using NVivo 9 qualitative analysis software, analyzed descriptively from a saturation grid, and used to evaluate men's P-TRT. Data from cognitive debriefing for five participants were used to evaluate the final conceptual model and validate the initial P-TRT instrument. Item saturation and theme exhaustion was achieved by 58 male participants of mean age 55.0 ± 10.0 (22-69) years who had used testosterone replacement therapy for a mean of 175.0 ± 299.2 days. The conceptual model was developed from items and themes obtained from the participant interviews and saturation grid. Items comprising eight dimensions were used for instrument development, ie, ease of use, effect on libido, product characteristics, physiological impact, psychological impact, side effects, treatment experience, and preference. Results from the testosterone replacement therapy preference evaluation provide a detailed insight into why most men preferred a topical gel product over an injection or patch. Items and themes relating to use of testosterone replacement therapy were in concordance with the final conceptual model and 29-item P-TRT instrument. The standard research approach used in this study produced the P-TRT instrument, which is suitable for further psychometric development and use in clinical practice.
    Patient Preference and Adherence 08/2012; 6:631-41. DOI:10.2147/PPA.S35840 · 1.68 Impact Factor
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    S.L. Szeinbach · E. Seoane-vazquez · K.H. Summers ·

    Value in Health 06/2012; 15(4):A200. DOI:10.1016/j.jval.2012.03.1080 · 3.28 Impact Factor
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    R.A. Puenpatom · S.L. Szeinbach · L. Ma · R. Ben-joseph · K.H. Summers ·

    Value in Health 06/2012; 15(4):A108. DOI:10.1016/j.jval.2012.03.587 · 3.28 Impact Factor
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    ABSTRACT: Compare direct and indirect costs of oxymorphone extended-release ('oxymorphone') and oxycodone controlled-release ('oxycodone') users. Patients, aged 18+, with ≥1 claim for oxymorphone/oxycodone, Q2:2006-Q4:2009, were selected from a de-identified private payer claims database and observed from the first such claim ('index date') until the earliest of: use of comparator drug; end of continuous eligibility; 12 months ('study period'). Patients with claims for any formulation of the comparator drug during the first 30 days of the study period were excluded. Direct (medical and drug) costs paid by private insurers were reported for patients aged 18-64 (n = 8354) and 65+(n = 3515), as well as sub-sets without cancer (n = 7090 and n = 2444, respectively). Indirect costs (medically-related absenteeism and disability) were reported for all employees, aged 18-64 (n = 1313), and employees without cancer (n = 1146). Multivariate models were used to estimate risk-adjusted costs controlling for patient characteristics. Oxymorphone users, aged 18-64, had lower drug costs ($693 vs $763, p = 0.0035) and similar medical costs ($1875 vs $1976, p = 0.3570) per patient-month compared with oxycodone users (mean follow-up 236 and 280 days, respectively). Indirect costs were not different ($662 vs $670, p = 0.9370). Oxymorphone users, aged 65+, had similar Medicare supplemental drug costs ($533 vs $588, p = 0.0840) and lower medical costs ($459 vs $747, p < 0.0001). Results were comparable for subsets without cancer. Patients with concomitant use of oxymorphone and oxycodone were excluded. Oxymorphone users incur lower risk-adjusted costs in several cost categories, compared with oxycodone users, and no higher costs in any of the examined categories.
    Journal of Medical Economics 02/2012; 15(1):87-95. DOI:10.3111/13696998.2011.629261 · 1.58 Impact Factor
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    ABSTRACT: Oxycodone controlled release (CR) and oxymorphone extended release (ER) are frequently prescribed long-acting opioids, which are approved for twice-daily dosing. The US Food and Drug Administration approved a reformulated crush-resistant version of oxycodone CR in April 2010.
    American Health and Drug Benefits 01/2012; 5(1):52-60.
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    ABSTRACT: A study was conducted to elucidate pharmacists' evaluation of panic disorder medications for recommendation to physicians. A mail questionnaire was used to collect the data from a nationally representative, geographically stratified random sample of 1,742 community pharmacists. Common factor analysis was used to analyze the interrelationships among 31 variables and to explain them in terms of their common underlying dimensions (factors). Seven factors explained 60.7% of the variance. The factor relating to efficacy considerations (e.g., documented clinical efficacy and obvious therapeutic response) explained 24.2% of the variance and was found to be important in pharmacists' recommendation of panic disorder drug products.
    Journal of Pharmaceutical Marketing & Management 12/2011; 8(3). DOI:10.3109/J058v08n03_05
  • Kent H. Summers · Sheryl L. Szeinbach · James H. Barnes ·
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    ABSTRACT: The objective of this study was to identify the manufacturer-related factors that may influence pharmacists' perceptions of retail pharmacy's professional image. A nationally representative sample of 455 community pharmacists (41.8% response rate) responded to a mailed survey. Twenty-one items were included in an exploratory factor analysis. The factors relating to therapeutic failures and manufacturers' pricing policies both had a negative impact on pharmacists' perceptions of professional image, while generic drug product and advertising factors had a more neutral impact. Recommendations regarding the future focus of pharmacist promotions are discussed.
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    ABSTRACT: Patients with osteoarthritis (OA) taking at least one CYP450-metabolized opioid concurrently with another CYP450-metabolized medication experience a drug-drug exposure (DDE), which puts them at risk of a pharmacokinetic drug-drug interaction (PK DDI). This study compared patients with and without such an incident DDE to determine healthcare utilization and associated payments. Using a retrospective database analysis, the impact of DDEs was evaluated in terms of associated clinical events, healthcare services utilization (office visits, outpatient visits, ED visits, hospitalization), and payments in patient populations based on age (those under age 65 and those 65 years of age and older), during the 6 months after exposure. DDE patients had significantly more inpatient hospitalizations than no-DDE patients. Mean total payments at 6 months were significantly higher for both younger and older patients with DDE compared to similar patients without DDE ($9,469, SD = $12,192 vs. $8,382, SD = $14,078, respectively, for younger patients, resulting in a difference of $1,087, P < 0.004, and $9,829, SD = $11,721 vs. $8,622, SD = $10,131, respectively, for older patients, resulting in a difference of $1,207, P = 0.001). In both age groups, DDE patients had significantly higher payments for nonopioid prescription drugs ($1,824 SD = $2,420 vs. $1,362, SD = $1,891, respectively, for younger patients, resulting in a difference of $462, P < 0.001, and $2,197 SD = $2,332 vs. $2,013, SD = $2,437, respectively, for older patients, resulting in a difference of $184, P = 0.020). Overall, patients with OA who experienced DDEs had significantly greater utilization rates of healthcare resources and higher associated payments in the 6-month observation period following the exposure, compared to patients without DDEs, consistent with the risk of PK DDIs associated with DDEs.
    Pain Practice 09/2011; 12(1):33-44. DOI:10.1111/j.1533-2500.2011.00498.x · 2.36 Impact Factor
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    ABSTRACT: Chronic low back pain (cLBP) patients who take at least 1 CYP450-metabolized opioid analgesic agent concurrent with at least 1 other CYP450-metabolized medication experience a drug-drug exposure (DDE), which puts them at risk for a pharmacokinetic drug-drug interaction (PK DDI). This study compared utilization of healthcare resources and associated payments in cLBP patients with and without incident DDEs with the potential to cause PK DDIs. A retrospective database analysis examined the associated clinical events, healthcare utilization (measured in terms of claims for office visits, outpatient visits, emergency department visits, and hospitalization), and cost to the health plan, as defined as the sum of health plan payments for resources used. Patients were grouped into 2 cohorts by age (those under 65 and those 65 years and over). In the 6 months after exposure, total healthcare payments were significantly higher for DDE patients than those without DDEs (no-DDE), in both in the younger ($7,086, SD = $8,370) and $6,353, SD = $8,352, respectively, P < 0.001) and the older cohorts ($7,806 vs. $7,043, respectively, P = 0.013). Younger and older patients with DDE had significantly higher prescription payments than those without DDE ($2,041, SD = $2,706 vs. $1,565, SD = $2,349, respectively, P < 0.001 for younger and $2,482, SD = $2,481 vs. $2,286, SD = $2,521, respectively, P = 0.044 for older patients). Both older and younger patients with DDE had significantly more claims for office visits and higher associated payments than similar patients without DDE. Patients in the study who experienced DDEs that placed them at risk for PK DDIs had significantly greater utilization rates of healthcare resources and higher associated payments in the 6-month observation period following exposure.
    Pain Practice 09/2011; 12(1):45-56. DOI:10.1111/j.1533-2500.2011.00503.x · 2.36 Impact Factor
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    ABSTRACT: The utilization of high-potency opioids is an important component of chronic pain management, and appropriate utilization of these medicines is a common concern of payers. Two of the most commonly prescribed oral long-acting opioids, oxycodone controlled-release (CR) and oxymorphone extended-release (ER), are FDA-approved for twice-daily dosing, which equates to a theoretical average consumption (DACON) of 2 tablets per day. DACON values greater than 2 have budget and policy implications for managed care pharmacists. To assess from the perspective of the pharmacy benefit decision maker the DACONs of oxycodone CR and oxymorphone ER. The main outcome measure for the analysis was DACON. Pharmacy and medical claims data from a large commercially insured population (i3 InVision Data Mart database) were analyzed to identify patients with at least 1 pharmacy claim for either oxycodone CR or oxymorphone ER from July 1, 2007, to September 30, 2009. After an initial 30-day titration period, all subjects included in the study had 1 or more claims totaling at least a 90-day supply of either study drug during the subsequent 90 days (DACON measurement period). Patients were excluded if there was evidence of a switch from one to the other study opioid during the 90-day measurement period. There were no limitations on the use of other opioids, either short- or long-acting, during either the DACON measurement period or the previous 6 months (baseline period). In addition, patients were excluded if the enrollee was younger than 18 years old, pregnant, did not have continuous insurance coverage for the 6 months before and after the start of the 90-day DACON measurement, or were enrolled in an HMO plan. Bivariate analyses were performed with between-group differences in DACON values assessed using t-tests and Wilcoxon rank sum tests. Patient characteristics including age, sex, geographic location, and baseline Charlson Comorbidity Index (CCI) for each drug group were evaluated descriptively using either the Pearson chi-square test or t-test. Multivariate analyses were conducted using generalized linear models (GLM) to adjust for the observed heterogeneity among patients in the observational database. For the GLMs, the gamma distribution and log link function were chosen to account for non-normal distributions of DACON. Independent variables included study drug, tablet strengths, age, sex, CCI, the maximum days gap between prescription refills during the DACON measurement period, and other opioid medication use. Several sensitivity analyses were conducted to verify all findings. The final analyses were conducted on 6,567 oxycodone CR patients and 796 oxymorphone ER patients. The unadjusted DACON mean value for the highest strength of oxycodone CR 80 milligrams (mg) was 3.9, compared with 2.9 for oxymorphone ER 40 mg (P < 0.001); mean DACON values were 3.0 versus 2.4, respectively, for lower strengths (P < 0.001) and 3.1 versus 2.5 for all strengths (P < 0.001). After adjusting for age, sex, CCI, maximum gap days, and other opioid medication use, a risk-adjusted mean difference in DACON remained, with oxycodone CR patients receiving on average 0.6 tablets more per day than those dispensed oxymorphone ER (P < 0.001). The direction, magnitude, and statistical significance of these differences were essentially unchanged in sensitivity analyses. On average during a 90-day time period, patients taking oxymorphone ER consumed 0.6 fewer tablets per day than did patients taking oxycodone CR. Further research is necessary to see if this difference amounts to cost savings for health plans that provide prescription reimbursement for patients with chronic pain syndromes.
    Journal of managed care pharmacy: JMCP 06/2011; 17(5):367-76. · 2.71 Impact Factor
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    ABSTRACT: Patients managing chronic non-cancer pain with cytochrome P450 (CYP450)-metabolized opioid analgesics who concurrently take another CYP450-metabolized medication experience a drug-drug exposure (DDE), which puts them at risk for a pharmacokinetic drug-drug interaction (PK DDI). This study examined the economic impact of incident DDEs with the potential to cause PK DDIs compared to similar patients without such exposure. This retrospective analysis used paid claims from a large, commercially insured population during January 1, 2004 through December 31, 2008. Propensity matching was used to control for baseline differences in comparisons between 85,043 exposed and 85,043 non-exposed patients. Comparisons yielded mean total costs 6 months after the DDEs that were significantly higher in subjects with DDE versus matched subjects without DDE [$8165 (SD $11,357) vs. $7498 (SD $11,668), respectively, p<0.01] resulting in a difference of $667. This was driven by medical costs [$5520 (SD $10,505) vs. $5222 (SD $10,689), respectively, p<0.01] a $298 difference, and total prescription costs [$2646 (SD $3262) vs. $2276 (SD $3907), respectively, p<0.01] a $369 difference. The study design demonstrates associations only and cannot establish causal relationships. Further, relevant DDEs were not included if concurrent consumption occurred outside the index period and when CYP450 substances were consumed that are not reflected in pharmacy claims (herbals, over-the-counter medications). Since concurrent exposure to DDEs with the potential to cause PK DDIs may be relatively common, policy decisions-makers should consider the use of long-acting opioids that are not metabolized through the CYP450 pathway.
    Journal of Medical Economics 05/2011; 14(4):390-6. DOI:10.3111/13696998.2011.583302 · 1.58 Impact Factor
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    M. Rubino · K. H. Summers · R. Ohsfeldt · R. Ben-Joseph · R. A. Puenpatom ·

    Value in Health 05/2011; 14(3). DOI:10.1016/j.jval.2011.02.362 · 3.28 Impact Factor
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    K. H. Summers · R. Ohsfeldt · R. A. Puenpatom · N. Rajan · R. Ben-Joseph ·

    Value in Health 05/2011; 14(3). DOI:10.1016/j.jval.2011.02.347 · 3.28 Impact Factor
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    Value in Health 05/2011; 14(3). DOI:10.1016/j.jval.2011.02.341 · 3.28 Impact Factor
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    ABSTRACT: Patients taking more than one drug metabolized through the cytochrome P450 (CYP450) enzyme system experience a drug-drug exposure (DDE), which puts them at risk for a potential pharmacokinetic drug-drug interaction (DDI), defined as two or more drugs interacting in such a way that the effectiveness and/or toxicity of one or all drugs are changed. Any patient subjected to a DDE is at risk for a potentially serious DDI, the epidemiology of which has not been thoroughly studied. Many drugs are metabolized primarily via the CYP450 enzyme system, including certain opioids used to manage moderate to severe chronic pain. We conducted a retrospective analysis of a large commercial claims database and a Medicare database to assess the prevalence of DDEs among patients with osteoarthritis taking CYP450-metabolized opioids. The overall prevalence of DDEs in this population was 26%, with females more likely to experience DDEs than males (28.4% vs. 21.0%, respectively). The number of unique concurrent prescriptions at baseline, gender, age, and Charlson Comorbidity Index were statistically significant predictors of DDEs (P < 0.05). This study challenged previous assumptions about DDEs in that advanced age was not positively associated with the risk of DDE. However, the number of prescriptions the patient received in the 90-day window prior to the index date was a risk factor. For patients taking at least two medications in the 90-day period prior to the index date, every additional prescription taken increased their risk for a DDE during the observation period by 138% (on average). The risk of DDE during the study period was threefold greater for patients with one medication in the 90-day period before index date compared with similar patients with no prescriptions in that same period before the index date. DDEs are more common than may be generally believed in patients with osteoarthritis, regardless of age, and can occur even in patients taking few medications. When selecting an opioid analgesic to treat osteoarthritis, physicians should consider the potential for exposure of these patients to drugs that could interact unfavorably. 
    Pain Practice 12/2010; 11(4):325-36. DOI:10.1111/j.1533-2500.2010.00438.x · 2.36 Impact Factor

Publication Stats

217 Citations
73.84 Total Impact Points


  • 2010-2013
    • Endo Pharmaceuticals
      Filadelfia, Pennsylvania, United States
    • Analysis Group
      Boston, Massachusetts, United States
  • 2011
    • Texas A&M University System Health Science Center
      • School of Rural Public Health
      Bryan, Texas, United States
  • 2008
    • Purdue University
      ウェストラファイエット, Indiana, United States