Primary Nonadherence to Statin Therapy: Patients' Perceptions

This study explores self-reported reasons for primary nonadherence among patients newly prescribed statin medication in an integrated health delivery system.
Published Online: April 15, 2013
Teresa N. Harrison, SM; Stephen F. Derose, MD, MS; T. Craig Cheetham, PharmD, MS; Vicki Chiu, MS; Southida S. Vansomphone, PharmD; Kelley Green, RN, PhD; Kaan Tunceli, PhD; Ronald D. Scott, MD; Elizabeth Marrett, MPH; and Kristi Reynolds, PhD, MPH
Objectives: To identify self-reported reasons for not filling a new prescription for statin therapy.


Study Design: A cross-sectional telephone survey.


Methods: Potential participants were identified from a randomized, controlled trial among Kaiser Permanente Southern California (KPSC) members aged >24 years with no  record of redeeming a new statin medication, defined as primary nonadherence. Among 1158 eligible patients, 98 were randomly selected and participated in a  semi-structured telephone interview that included questions on whether the respondent redeemed their statin prescription, why the patient may have chosen not to use a  KPSC pharmacy, reasons for not filling the prescription, use of non-prescription products for elevated cholesterol levels, and questions to assess health literacy.


Results: At 12 weeks post–index prescription date, 75% of 98 respondents reported not filling their new statin prescription, 20% reported picking it up from a non-KPSC  pharmacy, 4% had already picked up the prescription at a KPSC pharmacy, and 1% did not know if it had been filled. The 3 most commonly cited reasons for primary  nonadherence were general concerns about taking the medication (63%), a decision to try lifestyle modifications (63%), and fear of side effects (53%). A substantial proportion (33%) of respondents reported inadequate health literacy.


Conclusions: These data suggest the need for interventions that address patients’ negative perceptions of statins while emphasizing the benefits of statin therapy for  reducing cardiovascular morbidity and mortality in formats accessible to those with limited health literacy.


Am J Manag Care. 2013;19(4):e133-e139
This study highlights patients’ concerns about statins and a preference for lifestyle modifications among those who do not fill their first statin prescription.

  • Reasons for primary nonadherence to statin therapy are multifactorial; therefore, individualized interventions may be warranted.

  • Further research is needed to explore patient–physician communication about statintherapy, and the most appropriate communication methods and formats for different audiences.
Cardiovascular disease (CVD) is the primary cause of death in the United States.1 Furthermore, the total estimated direct and indirect costs of CVD and stroke in the United  States were $286 billion for 2007.2 Hypercholesterolemia is a well-known risk factor for CVD; the estimated prevalence of elevated low-density lipoprotein cholesterol  (LDL-C) levels among adults in the United States aged 20 years or more was 32% in 2008.2 Hydroxymethylglutaryl-coenzyme A reductase inhibitors (statins) are widely used  for management of elevated cholesterol levels and have been shown to be effective at preventing fatal and non-fatal cardiovascular events3-7 and potentially reducing  healthcare costs.8-10

The potential public health benefits of statin use are limited if there are patients who never fill newly ordered medication (primary nonadherence). While  most of the available evidence on nonadherence to statin therapy has focused on refill rates (secondary nonadherence), recent studies have shown that primary adherence  to statin therapy is suboptimal across a variety of populations.11-17 For example, among a large, diverse cohort of managed care patients in Southern California, 20% of  patients failed to fill their initial statin prescription.18 An evaluation of a community-based electronic prescribing initiative found that 28% of initial prescriptions for lipid-lowering  agents were never filled.11 A prospective study among military veterans given a new statin prescription found that 10% of the cohort reported having never started their medication.14

In addition to measuring the prevalence of primary nonadherence to statin therapy, understanding self-reported factors that result in unclaimed prescriptions is important for developing patient-focused interventions aimed at improving adherence and ultimately reducing adverse CVD events. While previous studies  have assessed sociodemographic, medical, and healthcare utilization characteristics associated with nonadherence to statins,19 to our knowledge, only 1 published study  has explored patients’ perceptions of statin therapy that contribute to primary nonadherence.15 Three additional studies assessed patients’ perceptions of statin therapy with  respect to nonadherence but these analyses combined patients who never filled their statin prescription and patients who discontinued their medication. 14,20,21 The aim of  our study was to explore self-reported reasons for primary nonadherence among patients with a newly prescribed statin medication, thus contributing to the scant literature on this topic.

METHODS

Setting


This study was conducted at Kaiser Permanente Southern California (KPSC), an integrated health delivery system which provides comprehensive care to more than 3.4million members at 14 medical centers and 197 medical offices. KPSC clinical practice guidelines for adult cholesterol management recommend statin treatment among all people with established coronary artery disease (CAD), diabetes mellitus (40 years or older), ischemic stroke or trans-ischemic stroke, abdominal aortic aneurysm,  peripheral artery disease, or carotid artery stenosis (>50%). In these patients, statins are recommended regardless of baseline LDL-C, and LDL-C goal is less than 100  mg/dL with an optional goal of less than 70 mg/dL. For patients with diabetes aged 39 years or under, patients with chronic kidney disease stages 4 or 5, and those with a 10-year CAD risk greater than 20%, statins are recommended with an LDL-C goal less than 100 mg/dL. For primary prevention patients who have a 10-year CAD risk less than 20%, the LDL-C goal is less than 130 mg/dL. Simvastatin was the preferred first-line statin for both primary and secondary prevention patients within KPSCduring the study. In addition, KPSC guidelines recommend lifestyle modifications in the management of adults with dyslipidemia.

Study Population

The sample for this study was  derived from KPSC members enrolled in a randomized controlled trial evaluating an automated system to increase adherence to newly prescribed statins using telephone  messaging and follow-up letters. The trial’s inclusion criteria are described in detail elsewhere.22 In brief, KPSC members were eligible for the trial if they were at least 24 years of age, had a new statin prescription that had not been filled at a KPSC pharmacy within 1 to 2 weeks of being ordered, had 12 months of continuous KPSC  membership prior to the statin order, and did not have a statin or statin combination drug dispensed within 365 days prior to the index  prescription date. A total of 5216 members were equally randomized to the intervention arm and a usual care arm. Members in the intervention arm received an automated telephone call followed up 1 week later by a letter for those who had not redeemed their statin medication at KPSC. Members were randomly selected for this study from  the 1158 participants in both arms of the randomized trial who had a new statin prescription ordered between May 10 and June 14, 2010, who had no record of redeeming  their statin medication 12 weeks after the prescription date and whose preferred language, according to administrative records, was English. Members could  have, however, redeemed their statin prescription between study selection and recruitment (a maximum of 5 days). Participants’ demographic characteristics were  captured through structured administrative databases. LDL-C measurements were obtained from electronic medical records closest to the date each member was  prescribed the new statin medication.

Recruitment

Between June 23 and July 30, 2010, we attempted to contact eligible members on a rolling basis for a brief telephone interview. Due to budget considerations, we aimed to complete 100 interviews. We made a maximum of 2 attempts over 5 days to contact each potential participant.

Two trained research staff used a survey instrument  consisting of scripted questions to assess 1) whether respondents redeemed their statin prescription, 2) why the patient may have chosen not to use a KPSC pharmacy,  3) reasons for not filling the prescription, 4) use of non-prescription products for cholesterol reduction, and 5) respondents’ health literacy (Appendix). To explore factors  that may have contributed to primary nonadherence, interviewers read a series of statements derived from the published literature23 about concerns with side effects, safety, effectiveness, and affordability, and asked respondents to indicate whether or not (yes/no) each reason applied to them. Responses to open-ended questions were recorded verbatim. Poor health literacy has been associated with low medication adherence,24 therefore we measured self-reported health literacy using a previously validated 3-item instrument that assesses problems due to reading, understanding, and filling out medical forms.25 The study protocol was approved by the  Institutional Review Board of Kaiser Permanente Southern California and informed consent was obtained by the telephone interviewer prior to the start of each interview.

Statistical Analysis

Summary statistics (means and proportions) were calculated for demographic characteristics (age, gender, race/ethnicity, education, and income), LDL-C, redemption of statin prescription, reasons for nonadherence, and use of non-prescription products to lower cholesterol. Responses to openended questions about reasons for primary  nonadherence were reported qualitatively.

Responses to each of the validated health literacy screening questions were scored on a scale of 1 to 5 and summed to create  an overall score that ranged from 1 to 15, with higher values representing better health literacy.25 The overall health literacy score was dichotomized as “adequate”  (score = 15), defined as the respondent reporting no problems, and “inadequate” (score <14).26 All analyses were performed using SAS statistical software version 9.2  (SAS Institute, Cary, North Carolina).

RESULTS

Among 1158 members eligible for interview, 23 were excluded during recruitment: 8 did not speak fluent English, 7 had a non-working telephone number, 5 were physically or mentally incapacitated, 2 had the statin prescription canceled by their physician, and 1 was deceased (Figure). We telephoned 379 eligible members, making 120 contacts. Of the 120 contacts, 22 refused to participate and 98 completed an interview. The overall response rate was 81.7%.

Demographic and clinical characteristics of the participants are provided in Table 1. The mean age among all survey respondents was 59.3 years (range: 29-97 years) and 46.9% were female. Nearly half of respondents were white, the large majority had at least a high school diploma, and approximately one-third had an annual household income of $50,000 or less. The mean (SD) LDL-C level closest to the date of enrollment in the randomized trial was 151 (36) mg/dL. T

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