Impact of Patient Financial Incentives on Participation and Outcomes in a Statin Pill-splitting Program
Published Online: June 01, 2007
Hae Mi Choe, PharmD; James G. Stevenson, PharmD; Daniel S. Streetman, PharmD; Michele Heisler, MD, MPA; Connie J. Standiford, MD; and John D. Piette, PhD
As medication costs continue to escalate, many institutions and managed care organizations are seeking to maximize the cost-effectiveness of individual pharmacotherapy. Pill-splitting programs have been implemented in various settings in an attempt to decrease medication costs.1-8 However, concerns have been raised that splitting could compromise patient safety due to uneven drug distribution in the split pills and loss of medication potency due to fragmentation.4 Although these concerns are legitimate for a fraction of the drugs available, for most medications, especially those with a long half-life, small variations due to fragmentation are not clinically important. In a randomized cross-over study, Rindone evaluated the impact of splitting lisinopril pills in 29 patients with hypertension; patients received a full pill for 2 weeks and a split pill for 2 weeks with no significant differences in systolic and diastolic blood pressures.5 Duncan et al evaluated the effects of pill splitting on low-density lipoprotein (LDL) and total cholesterol levels in a retrospective chart review of 125 patients receiving atorvastatin or simvastatin therapy who were switched to pill splitting. The results of that study demonstrated no statistically significant changes in LDL and total cholesterol levels.3 Another study conducted by Gee et al found that pill splitting of statins had no negative effects on patients' cholesterol profile.6
Concerns also have been raised about patient satisfaction and adherence with pill splitting.4 The few studies that examined these outcomes have reported variable results. McDevitt et al surveyed 94 patients with hypertension after 10 days of splitting their hydrochlorothiazide pills. Most of the subjects stated a preference for the commercially available lower-strength pills, and 77% reported a willingness to pay more for them.4 In contrast, Carr-Lopez et al reported that splitting lovastatin pills was easy to do and did not hinder medication adherence in the majority of patients.1 A study of fosinopril pill splitting reported no significant difference in medication adherence between patients who split pills and those who did not. In fact, the patients splitting fosinopril pills reported positive experiences.2 In the study by Gee et al, the majority of patients who split statin pills were satisfied and adherent to the new regimen.6
Although these prior studies provide some insight, the majority of studies to date were retrospective, were based on very small samples, or evaluated effects after brief periods of splitting pills. Finally, it is unclear whether patients who split pills will be more satisfied and adherent to their regimens if they share in the financial benefit associated with this change.
The objectives of this study were (1) to evaluate the impact of pill splitting on clinical measures, patient satisfaction, and acceptance and (2) to determine whether a financial incentive would affect patients' decision to split pills.
In the current study, we addressed the previously mentioned issues by using a large survey sample with a nested randomized trial of financial incentives to promote adherence to a pill-splitting statin regimen. First, we recruited patients with hyperlipidemia who were candidates for pill splitting, and we assessed their perceptions about pill splitting. Second, survey respondents were invited to participate in a randomized trial in which they would receive a free pill cutter, would be encouraged to split their lipid-lowering medication, and would have a 50% chance of being randomized to a group who received a reduction in copayment for the split-pill regimen. We compared the characteristics of patients who did and did not consent to participate in the pill-splitting trial. Trial participants were randomized to either pill splitting only or pill splitting plus a 50% reduction in their per-refill copayment. Randomization was done using a blocked randomization and random-number generator with random block sizes of 2, 4, or 6.
After 6 months, we compared patients with and without the copayment reduction in terms of their satisfaction with pill splitting and willingness to continue splitting pills. Finally, we examined pre-post changes in the adherence and lipid levels of patients in the trial to determine whether patients who split pills had any evidence of altered lipid control.
The study was conducted among patients using cholesterol-lowering medications (statins) in a university-based healthcare system. Statin use provides an ideal context in which to evaluate the outcomes of an incentive-based splitting program because these treatments are common, and many patients use brand-name drugs that are expensive to third-party payers. Moreover, hyperlipidemia has a clear, regularly measured physiologic outcome that can be used to quantify any potential negative effects of splitting on patients' health status.
Patient Identification and Recruitment
This study was approved by the University of Michigan Human Subjects Committee. Potential participants were identified through prescription claims data. Using these data, we identified all patients with 1 or more prescriptions written by a health center physician for atorvastatin, simvastatin, or pravastatin over a 6-month period. Lovastatin was excluded because at the time of the study drug costs varied according to the strength of the tablets. Crestor® was not included because it was not a preferred agent on the formulary. We excluded patients who changed health centers or prescription benefit plans, no longer took 1 of the study drugs, or were deceased. Approval from patients' primary care providers was obtained before patients were contacted regarding the study.
Eligible patients were sent a letter on health system letterhead and signed by the principal investigator. The letter explained the goals of the study and included consent forms, a brief baseline survey, a postage-paid reply envelope, and $5.00 as an incentive for returning the baseline survey. Patients did not have to agree to pill splitting to participate in the baseline survey.
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