Correlation between adherence to chemoprophylaxis and morbidity among patients with sickle cell disease in Webuye County Hospital, Kenya

Abstract

Background: According to the 2014 World Health Organization (WHO) estimate, 240,000 babies are born with SCD yearly in sub-Saharan Africa with most of them dying in early childhood. In Kenya, more than 80% of patients living with SCD are in the Western counties, where it is a major contributor to morbidity and mortality. Although SCD has been widely studied in Kenya, there is paucity of data on medication adherence and associated morbidity. Objective: To determine the relationship between adherence to chemoprophylaxis and morbidity among patients with SCD in Webuye County Hospital. Methods: A prospective observational study of 137 participants was done at the outpatient clinic in Webuye County Hospital. Participants who met the inclusion criteria were consecutively sampled. Sociodemographics were documented using interviewer-administered questionnaires. All participants were on proguanil and folic acid, those  5 years were on penicillin. Febrile illnesses, hospitalizations and blood transfusions were recorded over 6 months. Adherence was assessed using Brief Medication Questionnaire (BMQ) and participants dichotomized into adherent (n=97) and non-adherent (n=33). Data was analyzed using STATA version 14. Categorical variables were summarized as frequencies and percentages and continuous variables as means and median. Incidence risk ratios and Poisson regression compared clinical outcomes and adherence. A p value ≤0.05 was considered significant. Results: Participants’ median age was 5 years with (69)50.4% being male. Adherence to proguanil, folic acid and benzathine penicillin injection was 75.4%, 85.4% and 100% respectively. Non-adherence to folic acid increased the rate of hospitalizations (2.05 IRR; 95% CI 1.085 - 3.880, p = 0.027). Non-adherence to folic acid and proguanil increased the rate of blood transfusions (4.21 IRR; 95% CI 1.974 - 9.018, p  0.001) and (4.24 IRR; 95% CI 1.913 - 9.397, p  0.001) respectively. Non-adherence to folic acid and proguanil increased the rate of painful episodes (1.86 IRR; 95% CI 1.202 – 2.894, p = 0.005) and (1.52 IRR; 95% CI 1.011 – 2.290, p = 0.44) respectively. Non-adherence to folic acid and proguanil increased the rate of febrile illnesses (1.44 IRR; 95% CI 0.948 - 2.208, p = 0.086) and (1.33 IRR; 95% CI 0.907 - 1.976, p = 0.142) respectively. Conclusions: Adherence to benzathine penicillin, proguanil and folic acid was comparable to other studies. The non-adherent had a statistically significant increased rate of hospitalizations, blood transfusions and painful episodes. Recommendations: Adherence evaluation of all patients with SCD during routine care. Studies to identify causes and remedy of non-adherence to proguanil and folic acid.