Analysis of the comparative effectiveness of 3 oral bisphosphonates in a large managed care organization: adherence, fracture rates, and all-cause cost.

BACKGROUND: Despite widespread availability and use of oral bisphosphonates, fracture rates and associated medical costs are still high. Differences in fracture risk among these agents, if any, have not been quantified due to the lack of high-quality, head-to-head, randomized, controlled trials assessing this outcome. Randomized, placebo-controlled trials have shown that alendronate and risedronate reduce rates of both vertebral and nonvertebral fractures, whereas only reduction in vertebral fractures has been found for ibandronate. OBJECTIVE: To determine if there were any differences among 3 oral bisphosphonates in adherence, total cost of care, and effectiveness in reducing fracture rates in a large managed care population. METHODS: Administrative, longitudinal pharmacy and medical claims data were obtained from 14 geographically diverse health plans in the United States covering approximately 14 million members. Sampled members had at least 1 pharmacy claim for alendronate, risedronate, or ibandronate during the intake period (January 1, 2005, through October 31, 2007). The date of the first pharmacy claim for osteoporosis medications within the intake period was the index date. Members were followed for either 12, 24, or 36 months, depending on length of continuous health plan eligibility. Medication possession ratio (MPR) was measured using a total days supply that was calculated by multiplying the total quantity dispensed by the suggested days supply per unit of dispensing based on manufacturer-recommended dosing. For members who switched bisphosphonate strengths or medications, the estimated days supply was summed for all osteoporosis medications during the follow-up, including overlapping days supply. Outcomes included (a) the first incident fracture and percentages of members with at least 1 fracture after 6 months post-index; (b) the number of days from index to the first incident fracture, measured as time to event in Cox proportional hazards regression analysis; and (c) total all-cause health care costs (health plan allowed amount including member cost share). RESULTS: A total of 45,939 members were included (n = 24,909 alendronate, n = 13,834 risedronate, n = 7,196 ibandronate). In the 12-month analysis, MPRs were comparable (means = 0.57-0.58) for the 3 medications. After 24 months, MPRs had dropped for all medications, but those of both alendronate (mean = 0.50, 95% CI = 0.49-0.50) and risedronate (mean = 0.50, 95% CI = 0.49-0.51) were slightly higher than that of ibandronate (mean = 0.47, 95% CI = 0.46-0.48). At 36 months, again the MPRs had dropped for all 3 medications (means = 0.44-0.47) but were similar. There were no statistically significant differences among agents in the percentages of subjects with at least 1 fracture at 12, 24, or 36 months (36-month rates: alendronate 4.41%, risedronate 4.38%, ibandronate 6.28%, P = 0.102). The numbers of subjects with fracture(s) per month of follow-up were 0.0020 for alendronate, 0.0021 for risedronate, and 0.0022 for ibandronate (P = 0.087 overall). However, after adjusting for member characteristics, alendronate users had a 12% lower risk of experiencing any incident fracture than ibandronate users (hazard ratio = 0.88, 95% CI = 0.78-0.99, P = 0.034) within the follow-up period. In the first 12 post-index months, ibandronate users had higher mean [SD] unadjusted total all-cause health care costs ($7,464 [$15,975]) compared with alendronate ($7,233 [$16,671]) and risedronate ($ 6,983 [$16,870], P less than 0.001 for both comparisons), differences of approximately $19 per month and $40 per month, respectively. The results of the unadjusted 24-month analysis were similar, but there were no significant cost differences at 36 months. Total cost differences for the 3 medication groups were nonsignificant at 12, 24, and 36 months after adjusting for member characteristics. CONCLUSIONS: This retrospective analysis of an administrative claims database in a large managed care population showed similar rates of adherence and total adjusted all-cause health care costs for alendronate, risedronate, and ibandronate. Absolute unadjusted rates of fracture were small and did not significantly differ among agents, but after controlling for differences in member characteristics, the risk of fracture was 12% lower for alendronate users than for ibandronate users.

Adherence to oral antidiabetic therapy in a managed care organization: a comparison of monotherapy, combination therapy, and fixed-dose combination therapy.

BACKGROUND: Although medication adherence is one of the most important aspects of the management of diabetes mellitus, low rates of adherence have been documented. OBJECTIVE: This study sought to examine medication adherence among patients with diabetes mellitus in a managed care organization who were receiving antidiabetic monotherapy (metformin or glyburide), combination therapy (metformin and glyburide), or fixed-dose combination therapy (glyburide/metformin). METHODS: Medication adherence was evaluated through a retrospective database analysis of pharmacy claims. The adherence rate was defined as the sum of the days' supply of oral antidiabetic medication obtained by the patient during the follow-up period divided by the total number of days in the designated follow-up period (180 days). Health plan members were included in the analysis if they had an index pharmacy claim for an oral antidiabetic medication between August 1 and December 31, 2000, were continuously enrolled in the health plan, and were aged > or =18 years. A 6-month pre-index period was used to classify patients as newly treated or previously treated. Patients were grouped according to their medication-use patterns. RESULTS: After adjustment for potential confounding factors, including overall medication burden at index, there were no significant differences in adherence rates among 6502 newly treated patients receiving monotherapy, combination therapy, or fixed-dose combination therapy. Among the 1815 previously treated patients receiving glyburide or metformin monotherapy who required the addition of the alternative agent, resulting in combination therapy, adherence rates were significantly lower (54.0%; 95% CI, 0.52-0.55) than in the 105 patients receiving monotherapy who were switched to fixed-dose combination therapy (77.0%; 95% CI, 0.72-0.82). The 59 previously treated patients receiving combination therapy who were switched to fixed-dose combination therapy had a significant improvement in adherence after the switch (71.0% vs 87.0%; P < 0.001). CONCLUSIONS: In a managed care organization, previously treated patients receiving monotherapy with an oral antidiabetic medication who required additional therapy exhibited significantly greater adherence when they were switched to fixed-dose combination therapy compared with combination therapy. Patients receiving combination therapy who were switched to fixed-dose combination therapy exhibited significantly greater adherence after the switch.

Oral isotretinoin: an analysis of its utilization in a managed care organization.

OBJECTIVE: To assess utilization of oral isotretinoin within a managed care organization. METHODS: A retrospective analysis of pharmacy and medical claims from a southern California HMO was performed to (1) determine the prescribing patterns of oral isotretinoin from 1997 to 2000, stratified by age and gender, (2) categorize and quantify the use of antiacne prescriptions in the 6-month period immediately prior to the first oral isotretinoin prescription claim observed during this study; and (3) identify the amount of oral isotretinoin dispensed in a 210-day period following the dispensing date of the first oral isotretinoin prescription. RESULTS: The number of prescriptions was distributed almost equally between males and females, and the average number of prescriptions dispensed per patient decreased with age. A total of 39% of patients who received an oral isotretinoin prescription had not received a prescription for any antiacne medication in the preceding 6 months, and an additional 31% had not received a prescription for a topical retinoid. Approximately 27% of patients received more than a 150-day supply within the 210-day period following the first oral isotretinoin claim. CONCLUSIONS: These data suggest that in the 6 months preceding the first observed oral isotretinoin prescription, up to 70% of patients had not received a trial of a topical retinoid before receiving oral isotretinoin even though the product labeling advises that oral isotretinoin should be used only in patients unresponsive to.conventional therapy. (which is generally defined as at least a topical retinoid plus an oral antibiotic). Up to 27% of patients appeared to continue a course of treatment for longer than the 15-20 weeks advised in the isotretinoin product labeling.