Antiretroviral regimen complexity, self-reported adherence, and HIV patients’ understanding of their regimens: survey of women in the HERS study

9 December 2001. Related: Antiretrovirals.

Research regarding treatment adherence in chronic diseases, such as hypertension, suggests that increasing complexity in the medication regimen is associated with decreasing patient adherence. However, less is known about the relationship between regimen complexity and adherence in the treatment of HIV/AIDS.

This study confirms recent national reports that simplifying regimens is the most frequent strategy that HIV providers use to enhance their patients’ adherence to highly active antiretroviral therapy (HAART). The study examined the relationship between HAART regimen complexity and patient understanding of correct dosing to adherence (missing doses in the past 1 and 3 days).

Using a cross-sectional survey of the multi-centre, longitudinal cohort of the natural history of HIV disease in US women -the HIV Epidemiologic Research Study (HERS) -the authors implemented an instrument designed to survey drug adherence. The HERS adherence survey was administered by trained interviewers as a -one time only – questionnaire to all HIV-infected participants (regardless of medication use) at the visit that occurred between April 1, 1998 and December 31, 1998. Spanish- speaking interviewers administered a Spanish-language version of the survey instrument to participants whose first language was Spanish and who were not fluent in English. A total of 289 HIV-infected women in the HERS cohort completed the adherence survey. In terms of race/ethnicity: 53 percent of patients were black, 25 percent were white, and 17 percent were Latina.

Questions were asked about each medication taken.

For each medication each participant was asked to specify the way in which they were instructed to take the medication, both frequency and instructions about timing of dosing to food intake. Those not taking HAART answered questions about why they were not currently using the medication.

The two primary outcome variables measuring adherence with therapy were patient self-report of whether any antiretroviral medication doses had been skipped the previous day and in the previous three days. -Patient understanding – of the HAART dosing regimen was quantified using a binary outcome, based on whether the patient’s self-report of instructions related to taking the medication on an empty stomach and dosing frequency of their medications agreed with the standard prescribing practice. Use of drugs in which standard practice could vary was taken into account, and questions were adjusted to meet that variance.

The analysis consisted of basic summaries of patient characteristics, bivariate summaries of the relationship between dose skipping and various clinical and demographic factors and a logistic regression analysis to characterize the probability of skipping a dose as a function of patient-level variables simultaneously. The clinical and demographic factors included the Center for the Epidemiologic Study of Depression Inventory (CESD) collected on all HERS participants at each study visit.

Many of the patients were depressed; with 46 percent having a CESD score >23. The patients had a wide range of viral loads and CD4 counts immediately before collection of the adherence data. However, more than half had viral loads of <1000 copies/ml.

Nearly two-thirds of the patients (65%) were on a regimen that included three or more antiretrovirals; 64 percent were taking an antiretroviral regimen that contained at least one protease inhibitor. More than 40 percent of patients reported that they were prescribed a regimen that contained at least one medication that had to be taken three or more times daily. Fifteen percent reported that they were taking at least one medication that had to be taken on an empty stomach.

Only 75 percent correctly understood the dosing frequency; 80 percent correctly understood the food- dosing instructions, and 63 percent correctly understood both types of instructions. Many patients had skipped a dose recently; 24 percent had skipped a dose in the past 1 day (yesterday), and 32 percent had skipped a dose in the past 3 days.

The association between missing doses and patient characteristics showed that demographic, clinical and behavioural variables were not significant. Based on self- reported dosing instructions, there was no association between missing a dose and empty stomach instructions or maximum dose frequency.

Predictors of skipping doses were: 1) having a prior CD4 count of greater than 500; this CD4 level was associated with a lower likelihood of skipping doses in the previous 3 days; 2) younger age was also associated with lower likelihood of missing doses in the previous 3 days. According to the authors, -None of the other clinical, behavioural or demographic characteristics, including race/ethnicity, current of past injection drug use, or educational attainment was a significant predictor of missing doses in the previous 3 days in this model. –

Reference:

Stone VE, Hogan JW, Schuman P et al. Antiretroviral regimen complexity, self-reported adherence, and HIV patients’ understanding of their regimens: survey of women in the her study. J Acquir Immune Defic Syndr 2001 Oct 1;28(2):124-31.
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd= Retrieve&db=PubMed&list_uids=11588505&dopt=Abstract

Source: CDC HIV/AIDS, STD, TB Prevention News Update