Usage of central nervous system medication in HIV/AIDS patients: Longitudinal analysis (2005-2015) of prevalence and prescribing pattern changes

Abstract

The treatment of HIV/AIDS and coexisting psychiatric disorders is critical to the wellbeing of patients. There is currently a dearth of information on the scope of prescribing of central nervous system (CNS) medication among HIV-infected individuals in the South African private health sector, specifically the medical scheme environment. The general aim of the study was to determine possible changes in the prevalence and incidence rates of HIV/AIDS, and prescribing patterns of CNS medication in HIV/AIDS patients from 1 January 2005 to 31 December 2015 in the private health sector of South Africa. Retrospective medicine claims data from a pharmaceutical benefit management (PBM) company were used. The outcomes of the study will be presented in two manuscripts. Manuscript 1 conveyed on the findings of the investigation into the trends in the incidence and prevalence rate of HIV/AIDS patients. An open cohort of all patients with a diagnosis code for HIV/AIDS (ICD-10 codes B20-B24) and who claimed antiretroviral medication was used. Both HIV/AIDS incidence and prevalence rates were measured per 1 000 medical scheme beneficiaries for each year. Data were stratified by gender, age group and province. A total of 1 213 676 and 843 972 patients claimed medicine items in 2005 and 2015, respectively. In 2005, 0.63% (n = 7 665) of patients on the PBM database were HIV/AIDS patients and 2.10% (n = 17 302) in 2015. The prevalence rate of HIV/AIDS increased 3.3 times [6.3 (2005) to 20.5 (2015) per 1 000 medical scheme beneficiaries]. The incidence rate of HIV/AIDS also increased 2.3 times from 3.9 in 2006 to 9.1 per 1 000 medical scheme beneficiaries in 2015. The prevalence rate of HIV/AIDS among females had increased by more than three times over the study period, with a prevalence rate of 20.4 per 1 000 medical scheme beneficiaries in 2015. During the same period, the incidence rate of HIV/AIDS in female patients doubled, from 4.0 per 1 000 female medical scheme beneficiaries in 2006 to 8.5 in 2015, whereas the incidence rate among males rose from 3.9 in 2006 to 9.9 per 1 000 medical scheme beneficiaries in 2015. The age group ≥40 and <60 years had the highest HIV/AIDS prevalence rates of 14.4 in 2005 and 38.3 in 2015. This was followed by age group ≥60 and <70 years. The age group ≥0 and <6 years had the lowest HIV/AIDS prevalence rate. In the age group ≥18 and <40 years, the HIV/AIDS prevalence rate increased by 2.9 per 1 000 medical scheme beneficiaries between 2005 and 2015. The age group ≥40 and <60 years had the highest HIV/AIDS incidence rate of eight in 2006 and 18 per 1 000 medical scheme beneficiaries in 2015. Gauteng had the highest HIV/AIDS prevalence rate (422.4 per 1 000 medical scheme beneficiaries), followed by the Western Cape (149.4), and KwaZulu-Natal (118.4) in 2015. This study undoubtedly indicates an upward trend in the diagnosis and treatment of HIV/AIDS in the private medical scheme environment of South Africa from 2005 to 2015. Manuscript 2 reported the findings of the investigation into the prescribing patterns of CNS medication in HIV/AIDS patients. A longitudinal research design was followed to analyse retrospective CNS medicine claims data from a closed cohort (N = 308) of HIV/AIDS patients (identified with ICD-10 codes B20-B24) obtained from a PBM company’s database. Measures use to analyse CNS prescribing patterns were: i) differences between 2005 and 2015 in the prescribing of active pharmaceutical ingredients according to pharmacological and subpharmacological groups; ii) changes in mean number of medicine items per prescription per patient from 2010 to 2015; and iii) changes in the mean number of prescriptions per patient from 2010 to 2015, stratified per gender group. The results indicated that 86.68% of patients, including 144 (53.93%) females and 123 (46.07%) males, claimed one or more CNS prescriptions from 2005 to 2015. No associations were found between gender and the possibility to claim a CNS medication. The mean number of items per prescription per patient increased marginally from 2005 (1.22 (0.46) [1.15-1.28] to 2015 (1.25 (0.59) [1.16-1.33]) (P = 0.0004; Cohen’s < 0.8). The mean number of prescriptions per patient did not change significantly from 1.56 (1.57) (1.34-1.78] in 2005 to 1.93 (2.11) [1.65-2.22] in 2015 (P > .05). The majority of patients received an antidepressant during 2005 (49.68%) and 2015 (73.05%), with selective serotonin re-uptake inhibitors (15.26% vs. 25.00%) as the most prescribed antidepressant sub-pharmacological group for 2010 and 2015, respectively, followed by tricyclics (14.29% vs. 19.81%) and tetracyclic antidepressants (6.82% vs. 12.99%). Amitriptyline was the most prescribed individual active ingredient prescribed in 2015 (14.61%). The prescribing of bupropion, a tetracyclic antidepressant, had increased significantly (1.3% vs. 6.82%) from 2005 to 2015 (Ρ = 0.0007). The number of patients who received a sedative hypnotic, an anxiolytic or an anti-epileptic drug also increased with 45.0%, 54.55% and 89.94%, respectively, over the study period. This study indicates various prescribing patterns of CNS medication prescribing in privatelyinsured HIV/AIDS patients, for example an increase in the prescribing of antidepressants, sedative hypnotics, anxiolytics and anti-epileptic drugs that should be further investigated.