Unstable housing and substance use are associated with poor adherence to anti-HIV treatment regimens, according to a US study published in the August 1 st edition of the Journal of Acquired Immune Deficiency Syndromes.
Unlike many studies which have used a ‘snap-shot’ approach to determine levels of adherence in HAART-treated individuals, investigators in New York Sate conducted a longitudinal analysis of adherence over a three year period involving three separate assessments of adherence.
The study involved 435 HAART-treated individuals who were registered with the New York State Treatment Adherence Demonstration Project at ten separate adherence support programmes at hospitals and community organisations between January 1999 and March 2002. Patients had an average age of 43 years, 61% were men, 48% African-Americans, nearly 50% had received less than high-school education, and 22% reported that they did not have stable housing. Drugs were widely used, with 21% reporting crack, cocaine or heroin use in the three months before entry to the study, and 38% of individuals had a diagnosed mental health problem.
Adherence was assessed at baseline and then at two follow-up interviews. At each visit, individuals were asked to report their adherence in the previous three days, specifying which anti-HIV drugs they were taking, the number of pills and doses required for each medicine, and how many doses they had missed.
Five factors which could impact on adherence were also monitored. These were drug use, stress levels, housing status, belief in the efficacy of HAART, and alcohol use.
At baseline, 34.6% of patients were non-adherent, there was a significant fall to 27.4% (p
Overall, 53.9% of individuals reported being non-adherent at least once, with 27.5% none-adherent once, 18% none-adherent at two visits, and 8.1% none-adherent at all three visits.
Patients who reported non-adherence at baseline were three times more likely to report poor adherence at the first follow-up visit than adherent individuals.
A relationship between all the five factors the investigators had tested for was found with non-adherence. However, the investigators also found that it was lack of stability which most significantly increased the odds of non-adherence. Patients who started to use drugs in the course of the study had an odds ratio of non-adherence of 3.18; those losing stable housing an odds ratio of non-adherence of 2.97; patients experiencing greater stress had an odds ratio of non-adherence of 2.93; and, individuals who started to frequently drink alcohol, an odds ratio of non-adherence of 2.92.
Adherence in ‘stable’ drug users, who reported drug use at baseline and follow-up visits was, by contrast, not significantly different from the level recorded in non-users.
Patients who doubted the efficacy of HAART were also likely to have poor adherence, with an odds ratio of non-adherence of 3.2 compared to patients who believed taking their medicines was worthwhile. No demographic variables were predictive of non-adherence.
The investigators conclude that adherence should be assessed over time, and that multiple barriers to optimal levels of adherence exist, emphasising, “for at least some clients, it may be instability in these factors, rather than simply their presence or absence that contributes to nonadherence.”
Further information on this website
Adherence - factsheet
Adherence tips - factsheet
Missed/late doses - factsheet
Adherence - booklet in the information for HIV-positive people series (pdf)
Tesoriero J et al. Stability of adherence to highly active antiretroviral therapy over time among clients enrolled in the Treatment Adherence Demonstration Project. JAIDS 33: 484 – 492, 2003.