Unstructured treatment interruption: An important risk factor for arterial stiffness in adult Malawian patients with antiretroviral treatment: An important risk factor for arterial stiffness in adult Malawian patients with antiretroviral treatment

Objectives: The aim of the study was to evaluate the impact of unstructured antiretroviral treatment (ART) interruption on arterial stiffness in adult Malawians who are on ART for at least 35 years. Design: The number of treatment interruption events for at least 60 days during ART treatment was quantified in patients for at least 35 years using retrospective routinely collected clinic data. Treatment interruption data were linked to patient carotid-femoral pulse wave velocity (PWV);PWVmore than 10 m/s was set as the threshold for clinically significant cardiovascular disease risk. Methods: PWV was measured in patients (on ART≥18 months), during routine ART clinic visits in Blantyre, Malawi, between November 2014 and July 2015. Multivariable linear regression was used to estimate the change in PWV m/s associated with treatment interruption. Multivariable logistic regression was used to estimate risk of PWV more than 10 m/s. All models were controlled for demographic and cardiometabolic risk factors. Results: In 220 patients (median age 45 years, range 37-80 years), 86 (37.4%) patients had at least one treatment interruption event. Median length of treatment interruption events was 75 days (range 31 days to 8 years). Overall, 31 (14%) patients had a PWV more than 10 m/s. In multivariable analysis, we found a 0.2 increase in PWV m/s per treatment interruption event (0.2, 95% confidence interval 0.1-0.4) and a two-fold increased risk of PWV more than 10 m/s per treatment interruption event (adjusted odds ratio 2.2, 95% confidence interval 1.2-4.0). Conclusion: Treatment interruption in patients with ART for at least 35 years is a common and important risk factor for arterial stiffness. Therefore, the link between treatment interruption and cardiovascular disease in this setting in which traditional risks factors are less prevalent needs to be explored further.