Glatiramer acetate and interferon beta-1a for intramuscular administration: a study of outcomes among multiple sclerosis intent-to-treat and persistent-use cohorts

Abstract

Objective:

To study outcomes of multiple sclerosis (MS) patients treated with either glatiramer acetate (Copaxone) or interferon beta-1a for once-weekly, intramuscular administration (Avonex).

Methods:

An ‘intent-to-treat’ (ITT) cohort (n?=?1282) was established, consisting of patients diagnosed with MS who began therapy on either glatiramer acetate (GA) or intramuscular interferon beta-1a (IFN beta-1a-IM) and had continuous insurance coverage from 6 months before to 24 months after the date when they began taking the medication. A ‘persistent use’ (PU) cohort (n?=?639) was also constructed, consisting of individuals who, in addition to the criteria listed above, had a claim for GA or IFN beta-1a-IM within 28 days of the end of the 2-year post-period. Data were obtained from the i3 InVision Data Mart Database from July 2001 to June 2006. Multivariate regressions were used to examine both the 2-year total direct medical costs and the likelihood of relapse associated with the use of each of these alternative MS medications. A relapse was defined as either being hospitalized with a principal diagnosis of MS or having an outpatient visit with a MS diagnosis followed within 7 days by a claim for a corticosteroid. All regressions controlled a wide range of factors that may potentially affect outcomes.

Results:

In the ITT cohort, patients who started therapy on GA had a significantly lower 2-year risk of relapse (10.01 vs. 5.18%; p?=?0.0034) as well as significantly lower 2-year total medical costs ($44,201 vs. $41,121; p?=?0.0294). In the PU cohort, patients who used GA also had a significantly lower 2-year risk of relapse (7.25 vs. 2.16%; p?=?0.0048) as well as significantly lower total medical costs ($67,744 vs. 63,714; p?=?0.0445).

Limitations:

The analyses relies on an administrative claims database of an insured population and hence, may not be generalizeable to other populations. In addition, such a database precludes measurement of lost work time, unemployment, caregiver burden or other costs associated with MS.

Conclusions:

Results from this study indicate that the use of GA is associated with significantly lower probability of relapse as well as significantly lower 2-year total direct medical costs than IFN beta-1a-IM.     

The impact of persistence with therapy on inpatient admissions and emergency room visits in the US among patients with multiple sclerosis

Objective:

Disease-modifying therapy (DMT) for multiple sclerosis (MS) can reduce relapses and delay progression; however, poor adherence and persistence with DMT can result in sub-optimal outcomes. The associations between DMT adherence and persistence and inpatient admissions and emergency room (ER) visits were investigated.

Methods:

Patients with MS who initiated a DMT in a US administrative claims database were followed for 1 year. Persistence to initiated DMT was measured as the time from DMT initiation to discontinuation (a gap of >60 days without drug ‘on hand’) or end of 1-year follow-up. Adherence to initiated DMT was measured during the persistent period and was operationalized as the medication possession ratio (MPR). Patients with an MPR <0.80 were considered non-adherent. Claims during the 1-year follow-up period were evaluated for the presence of an all-cause inpatient admission or an ER visit. Adjusted odds ratios (AORs) for inpatient admission or ER visit comparing persistent vs non-persistent and adherent vs non-adherent patients were estimated using logistic regression models adjusted for patient characteristics.

Results:

The final sample included 16,218 patients. During the 1-year follow-up period, 35.3% of patients discontinued their initiated DMT and 13.9% were not adherent while on therapy. During that same period, 10.0% of patients had an inpatient admission and 24.9% had an ER visit. The likelihoods of inpatient admission and ER visit were significantly decreased in persistent patients (AOR [95% CI]?=?0.50 [0.45, 0.56] and 0.65 [0.60, 0.69], respectively) and in adherent patients (AOR [95% CI]?=?0.83 [0.71, 0.97] and 0.86 [0.77, 0.95], respectively).

Conclusions:

Persistence and adherence with initiated DMT are associated with decreased likelihoods of inpatient admission or ER visit, which may translate to improved clinical outcomes.     

Adherence,persistence, healthcare utilization,and cost benefits of guideline-recommended hepatitis B pharmacotherapy

Abstract

Objective:

To compare pharmacotherapy adherence, persistence, and healthcare utilization/costs among US patients with chronic hepatitis B (CHB) initiated on an oral antiviral monotherapy recommended as first-line treatment by current national (US) guidelines vs an oral antiviral not recommended as first-line monotherapy.

Research design and methods:

In this retrospective cohort study, patients aged 18–64 with medical claims for CHB who initiated an oral antiviral monotherapy for CHB between 07/01/05 and 01/31/10 were identified from a large US commercial health insurance claims database. Patients were continuously enrolled for a 6-month baseline period and ≥ 90 days follow-up. They were assigned to ‘currently recommended first-line therapy’ (RT: entecavir or tenofovir) or ‘not currently recommended first-line therapy’ (NRT: lamivudine, telbivudine, or adefovir) cohorts.

Main outcome measures:

Multivariate analyses were conducted to compare treatment adherence, persistence, healthcare utilization, and costs for RT vs NRT cohorts.

Results:

Baseline characteristics were similar between RT (n?=?825) and NRT (n?=?916) cohorts. In multivariate analyses, RT patients were twice as likely as NRT patients to be adherent (OR?=?2.09; p?<?0.01) and persistent (mean: RT?=?361 days, NRT?=?298 days; p?<?0.01) and half as likely to have an inpatient stay (OR?=?0.527; p?<?0.01). Between the two oral antivirals recommended as first-line treatment, even though pharmacy cost was higher for entecavir, mean total healthcare costs for entecavir and tenofovir were similar ($1214 and $1332 per patient per month, respectively). Similar results were also observed with regard to adherence, persistence, and healthcare use for entecavir and tenofovir.

Conclusions:

A limitation associated with analysis of administrative claims data is that coding errors can be mitigated but are typically not fully eradicated by careful study design. Nevertheless, the current findings clearly indicate the benefits of initiating CHB treatment with an oral antiviral monotherapy recommended as first-line treatment by current guidelines.     

Impact of a step-therapy protocol for pregabalin on healthcare utilization and expenditures in a commercial population

Abstract

Objective:

To compare changes in healthcare resource utilization and costs among members with painful diabetic peripheral neuropathy (pDPN), postherpetic neuralgia (PHN), or fibromyalgia (FM) in a commercial health plan implementing pregabalin step-therapy with members in unrestricted plans.

Methods:

Retrospective study of outcomes associated with implementation of a pregabalin step-therapy protocol using claims data from Humana (‘restricted’ cohort) and Thomson Reuters MarketScan (‘unrestricted’ cohort). Members aged 18–65 years receiving treatment for pDPN, PHN, or FM during 2008 or 2009 were identified; cohorts were matched on diagnosis and geographic region. Baseline to follow-up changes in healthcare resource utilization and costs were determined using difference-in-differences (DID) analysis. Statistical models adjusting for covariates explored relationships between restricted access and outcomes.

Results:

A total of 3876 restricted cohort members were identified and matched to 3876 unrestricted cohort members. FM was the predominant diagnosis (84.7%). The unrestricted cohort was older (mean?=?49.0 (SD?=?10.4) years vs 47.6 (SD?=?10.5) years; p?<?0.001), and had greater comorbidity (RxRisk-V score?=?5.4 (SD?=?3.2) vs 4.4 (SD?=?2.9), p?<?0.001) than the restricted cohort. Compared with the unrestricted cohort, the restricted cohort demonstrated a greater year-over-year decrease in pregabalin utilization (?2.6%, p?=?0.008), and greater increases in physical therapy and disease-related outpatient utilization (3.7%, p?=?0.010 and 3.6%, p?=?0.022, respectively). There were no statistically significant net differences in all-cause or disease-related total healthcare, medical, or pharmacy costs between cohorts. After adjusting for baseline compositional differences between cohorts, restricted plan membership was associated with a net increase in all-cause medical ($1222; p?=?0.016) and disease-related healthcare costs ($859; p?=?0.002). Limitations include use of a combined analysis for pDPN, PHN, and FM, especially since the observed results were likely driven by FM; an inability to link the prescribing of a medication with the condition of interest, which is common to claims analyses; and lack of pain severity information.

Conclusions:

Implementation of a pregabalin step-therapy protocol resulted in lower pregabalin utilization, but this restriction was not associated with reductions in total healthcare costs, medical costs, or pharmacy costs.     

Comparison of second-generation antipsychotic treatment on psychiatric hospitalization in Medicaid beneficiaries with bipolar disorder

Abstract

Objective:

To compare second-generation antipsychotics on time to and cost of psychiatric hospitalization in Medicaid beneficiaries with bipolar disorder.

Methods:

Retrospective study using healthcare claims from 10 US state Medicaid programs. Included beneficiaries were aged 18–64, initiated a single second-generation antipsychotic (aripiprazole, olanzapine, quetiapine, risperidone, or ziprasidone) between 1/1/2003–6/30/2008 (initiation date?=?index), and had a medical claim with an ICD-9-CM diagnosis code for bipolar disorder. A 360-day post-index period was used to measure time to and costs of psychiatric hospitalization (inpatient claims with a diagnosis code for a mental disorder [ICD-9-CM 290.xx–319.xx] in any position). Cox proportional hazards models and Generalized Linear Models compared time to and costs of psychiatric hospitalization, respectively, in beneficiaries initiating aripiprazole vs each other second-generation antipsychotic, adjusting for beneficiaries’ baseline characteristics.

Results:

Included beneficiary characteristics: mean age 36 years, 77% female, 80% Caucasian, aripiprazole (n?=?2553), mean time to psychiatric hospitalization or censoring?=?85 days; olanzapine (n?=?4702), 81 days; quetiapine (n?=?9327), 97 days; risperidone (n?=?4377), 85 days; ziprasidone (n?=?1520), 82 days. After adjusting for baseline characteristics, time to psychiatric hospitalization in beneficiaries initiating aripiprazole was longer compared to olanzapine (hazard ratio [HR]?=?1.52, p?<?0.001), quetiapine (HR?=?1.40, p?<?0.001), ziprasidone (HR?=?1.33, p?=?0.032), and risperidone, although the latter difference did not reach significance (HR?=?1.18, p?=?0.13). The adjusted costs of psychiatric hospitalization in beneficiaries initiating aripiprazole were significantly lower compared to those initiating quetiapine (incremental per-patient per-month difference?=?$42, 95% CI?=?$16–66, p?<?0.05), but not significantly lower for the other comparisons.

Limitations:

This study was based on a non-probability convenience sample of the Medicaid population. Analyses of administrative claims data are subject to coding and classification error.

Conclusions:

Medicaid beneficiaries with bipolar disorder initiating aripiprazole had significantly longer time to psychiatric hospitalization than those initiating olanzapine, quetiapine, or ziprasidone, and significantly lower adjusted costs for psychiatric hospitalization than those initiating quetiapine.     

Inflammatory bowel disease: healthcare costs for patients who are adherent or non-adherent with infliximab therapy

Objective:

Healthcare costs of inflammatory bowel disease are substantial. This study examined the effect of adherence versus non-adherence on healthcare costs in patients with inflammatory bowel disease.

Methods:

Adults who started infliximab treatment between 2006 and 2009 and had a diagnosis of inflammatory bowel disease were identified from MarketScan Databases. Medication adherence was defined as an infliximab medication possession ratio of 80% or greater in the first year. Mean treatment effects (adherence versus non-adherence) on costs in adherent patients were estimated with propensity-weighted generalized linear models.

Results:

A total of 1646 patients were identified. Significant variables in the model used to develop propensity weights were age, year of infliximab initiation, having Medicare coverage, presence of supplementary diagnoses, office as the place of service for infliximab initiation, prior aminosalicylate use, prior outpatient costs, number of prior outpatient visits, and number of prior colonoscopies. Mean total costs in adherent (n?=?674) and propensity-weighted non-adherent (n?=?972) patients were $41,713 versus $47,411 overall (p?p?p?p?p?p?=?0.460).

Limitations:

Costs associated with infliximab administration (infusions, adverse events) were captured in healthcare costs (inpatient, outpatient, and emergency room), not in infliximab costs. The influence of adherence on indirect costs (e.g., time lost from work) could not be determined. Reasons for non-adherence were not available in the database.

Conclusions:

In patients who were adherent to infliximab treatment (a medication possession ratio of 80% or greater in the first year), adherence versus non-adherence was associated with lower total healthcare costs, supporting the overall value of infliximab adherence in patients with inflammatory bowel disease.     

Using observational analysis of multiple sclerosis relapse to design outcomes-based contracts for disease-modifying drugs: a feasibility assessment

Abstract

Objective:

To assess predictors and costs of multiple sclerosis (MS) relapse, a potential outcome measure in payer-manufacturer risk-sharing agreements for disease-modifying drugs (DMDs).

Methods:

A retrospective cohort analysis of medical/pharmacy claims was used. Study patients had ≥1 DMD (interferon beta, glatiramer, natalizumab) claim, without DMD claims in a 6-month pre-period before DMD initiation; were aged 18–64 years and continuously enrolled from the pre-period through a 24-month post-period; and had ≥2 MS medical claims during the 30-month study period. Post-period relapse cohorts included: (1) severe (hospitalization with MS diagnosis); (2) moderate (outpatient services including intravenous methylprednisolone); and (3) none. Poisson regression modeled severe relapse frequency, logistic regression modeled ≥1 severe relapse, and generalized linear modeling predicted healthcare costs. Tested predictors included demographics, insurance type, index DMD, pre-period health status, and DMD medication possession ratio (MPR).

Results:

Severe relapse was experienced by 14.5% and moderate relapse by 13.8% of 2291 patients. In logistic regression, severe relapse was predicted by plan type; age (odds ratio [OR]?=?1.018, 95% confidence interval [CI]?=?1.005–1.031); pre-period Charlson Comorbidity Index (OR?=?1.307, 95% CI?=?1.166–1.464); pre-period proxy measure indicating impaired activities of daily living (OR?=?1.470, 95% CI?=?1.134–1.905); pre-period MS hospitalization (OR?=?2.174, 95% CI?=?1.537–3.074); and DMD non-adherence (MPR OR?=?0.101, 95% CI?=?0.068–0.151). Poisson regression results were similar. Predicted mean [standard deviation] all-cause healthcare expenditures were tripled for patients with severe compared with moderate relapse ($48,173 [$8665] and $13,334 [$1929], respectively).

Limitations:

Commercially insured patients from a single payer; use may have been inconsistent with approved indications; proxy relapse measure may have misclassified patients.

Conclusions:

Severe MS relapses requiring hospitalization, although affecting less than 15% of patients initiating DMD treatment, are associated with high medical costs. The only actionable predictor of severe relapse identified in observational analysis was MPR, raising questions about the feasibility of using observational data to guide outcomes-based contracting.     

Glycemic control among patients with type 2 diabetes who initiate basal insulin: a retrospective cohort study

Objective:

To examine changes in glycemic control for patients with type 2 diabetes mellitus (T2DM) after initiation of basal insulin and factors associated with improved glycemic control.

Methods:

An analysis of retrospective medical records of patients with T2DM was examined using Humedica’s electronic medical records database (January 2007–August 2012). Patients with T2DM, initiating basal insulin, age ≥21 years, with a recorded HbA1c test in both the 1 year prior and the 2 years post-initiation were included. A multivariate regression examined factors associated with changes in glycemic control. Logistic regressions examined factors associated with improvements or worsening of glycemic control, compared to relatively unchanged glycemic control.

Results:

Many (14,457) individuals met the inclusion–exclusion criteria. Multivariate analyses revealed that older age (p?p?p?=?0.0138), and higher household income (p?=?0.0065) were associated with improved glycemic control. Patients diagnosed with comorbid peripheral vascular disease (p?=?0.0072), cancer (p?=?0.0019), obesity (p?=?0.0002), moderate (p?=?0.0103), and severe chronic kidney disease (p?p?=?0.0075) in the pre-period were found to have significantly improved glycemic control in the post-period. Use of prandial insulin (p?=?0.0087), pre-mix insulin (p?=?0.0003) in the pre-period, a higher pre-period HbA1c score (p?p?Limitations:

Analyses rely on electronic medical records which cannot capture patient healthcare utilization occurring outside of the data capture system. Analyses do not control for insulin dosage or type of basal insulin prescribed.

Conclusions:

Among patients with T2DM treated with basal insulin, a number of factors may influence glycemic outcomes. These findings suggest a role for a more personalized approach to the treatment of patients with T2DM.     

Further validation of the psychometric properties of the Bowel Function Index for evaluating opioid-induced constipation (OIC)

Abstract

Objective:

The BFI (Bowel Function Index) is a 3-item questionnaire for assessing opioid-induced constipation (OIC). The aim of this study was to contribute to the validation of the psychometric properties of the BFI by confirming a constipation threshold, and through correlation with other validated tools: KESS (Knowles Eccersley Scott Symptom) score and generic (12-Item Short Form Health Survey, SF-12) and specific (Patient Assessment of Constipation–Quality of Life, PAC-QoL) quality-of-life scores.

Methods:

A survey on opioid-requiring cancer-patients was carried out in France. A questionnaire was filled out for all patients that recorded their demographic characteristics, an assessment of their constipation using BFI and KESS scores, and included a self-assessment of quality-of-life using PAC-QoL and SF-12. Correlation of BFI with KESS, PAC-QoL, and SF-12 was investigated.

Results:

Five hundred and twenty patients participated in the entire data collection with no loss. BFI was shown to be statistically correlated (r?=?0.571; p?<?0.0001) with the KESS score and matches up with PAC-QoL and to a lesser extent with the SF-12 generic quality-of-life questionnaire. A BFI threshold of 27–29 to discriminate constipated from non-constipated patients was confirmed.

Key limitations:

This cross-sectional study in a selected population of cancer pain patients has validated the psychometric properties of the BFI. Further confirmation of the validity of the BFI could be sought through the use of longitudinal studies, and larger populations, such as non-cancer pain patients treated with opioids.

Conclusion:

This study contributes to the validation of the psychometric properties of the BFI. It confirms the BFI as an easy-to-use tool to assess constipation and its impact on quality-of-life in chronic pain patients.     

Cost comparison of prostaglandin analogues: a Canadian population-based analysis

Abstract

Objectives: Glaucoma is a fairly common disease, however, little is known about the costs associated with prostaglandin analogues (PAs). The costs between the three available PAs (Lumigan® (bimatoprost), Xalatan® (latanoprost) and Travatan® (travoprost)) were compared as monotherapy and when adjunctive therapy was used.

Methods: From the Québec drug claims database, all patients who used these drugs for 1 full year were identified. From the Ministry of Health (MoH) perspective, the average cost for all reimbursed costs (drug costs and pharmacist fees) were calculated. Those costs plus the patient out-of-pocket copayments were used for the payer + user (PU) perspective.

Results: Data from 4,653 patients were analysed (3,606 on monotherapy and 1,047 on combination treatment with adjunctive therapy), 59.7% were females, and the average age was 72.6 ± 10.4 years. MoH perspective costs were $410 ± $167 for bimatoprost, $381 ± $145 for latanoprost and $298 ± $121 for travoprost (all differences p<0.001), for patients on monotherapy. Costs of combination treatment with adjunctive therapy were $786 ± $416, $686 ± $313, and $623 ± $521, respectively (travoprost significantly lower than each of the other two p<0.001, others=not significant). Results from the PU perspective were comparable.

Conclusions: Travoprost had the lowest cost, both as monotherapy and in conjunction with other glaucoma treatments. Further comparative pharmacoeconomic evaluation is warranted.     

Economic outcomes of exenatide vs liraglutide in type 2 diabetes patients in the United States: results from a retrospective claims database analysis

Abstract

Objective:

The safety and efficacy of the GLP-1 receptor agonists exenatide BID (exenatide) and liraglutide for treating type 2 diabetes mellitus (T2DM) have been established in clinical trials. Effective treatments may lower overall treatment costs. This study examined cost offsets and medication adherence for exenatide vs liraglutide in a large, managed care population in the US.

Methods:

This was a retrospective cohort analysis comprising adult patients with T2DM who initiated exenatide or liraglutide between 1/1/2010 and 6/30/2010 and had 6 months pre-index and post-index continuous eligibility. Patients were propensity score-matched to controls for baseline differences. Medication adherence was measured by proportion of days covered (PDC). Paired t-test and McNemar’s test were used to compare outcomes.

Results:

Matched exenatide and liraglutide cohorts (n?=?1347 pairs) had similar average total 6-month follow-up costs ($6688 vs $7346). However, exenatide patients had significantly lower mean pharmacy costs ($2925 vs $3272, p?<?0.001). Among liraglutide patients, patients receiving the 1.8?mg dose had significantly higher average total costs compared to those receiving the 1.2?mg dose ($8031 vs $6536, p?=?0.026), with higher mean pharmacy costs in the 1.8?mg cohort ($3935 vs $3146, p?<?0.001). There were no significant differences in inpatient or outpatient costs or medication adherence between groups (mean PDC: exenatide 56% vs liraglutide 57%, p?=?0.088).

Limitations:

The study assumed that all information needed for case classification and matching of cohorts was present and not differential across cohorts. The study did not control for covariates that were unavailable, such as HbA1c and duration of diabetes.

Conclusions:

Patients initiating exenatide vs liraglutide for T2DM had similar medication adherence and total healthcare costs; however, exenatide patients had significantly lower total pharmacy costs. Patients prescribed 1.8?mg liraglutide had significantly higher costs compared to those on 1.2?mg.