Tuberculosis patients in South Africa have a high prevalence of psychological distress
Question: What are the prevalence and predictors of psychological distress in people with tuberculosis in South Africa?
Population: In total 4935 patients, aged between 18 and 93 years, within 1 month of initiating first time treatment or retreatment for tuberculosis.
Setting: Public primary care clinics, South Africa; April–October 2011.
Assessment: Psychological distress was assessed using the Kessler Psychological Distress Scale (K-10), a 40-point scale with higher scores denoting greater psychological distress. Cut-off values of 16 and 28 points were used to identify individuals with likely clinical and subclinical anxiety and/or depression, based on previous validation studies in South Africa. Data were collected on potential predictors of psychological distress, including: age, gender, educational attainment, marital status, income, poverty, alcohol consumption and tobacco use. Poverty was assessed by five items asking about the availability or non-availability of shelter fuel or electricity, clean water, food and cash income in the past week. Alcohol consumption was assessed using the 10-item Alcohol Disorder Identification Test. Variables identified as significant in univariate analysis were included in multivariable regression models.
Outcomes: Prevalence and predictors of psychological distress.
Of the 4935 included participants, 4900 (99.3%) agreed to participate. The prevalence of psychological distress (defined as a score ≥28 on the K-10 scale) was 32.9%. Multivariable analysis using this definition found significantly increased odds of psychological distress among: patients aged 45 years, compared with those aged 18–30 years (OR 1.52, 95% CI 1.24 to 1.85); patients with a high degree of poverty, compared with those with low poverty ratings (OR 1.90, 95% CI 1.57 to 2.31). Variables associated with significantly lower odds of psychological distress included: being married or cohabitating, compared with being unmarried (OR 0.74, 95% CI 0.62 to 0.87) and educational attainment of grade 8–11, compared with attainment of grade 7 or less (OR 0.77, 95% CI 0.65 to 0.91). Gender; a marital status of separated, widowed or divorced; educational attainment of grade 12 or more, and daily tobacco use were not significant predictors of psychological distress at this cut-off value. Using a cut-off value of 16 points on the K-10, the prevalence of psychological distress was 81.1%. Multivariable analysis indicated that significant predictors of distress at this definition included: aged ≥45 years (OR 1.30, 95% CI 1.00 to 1.69); high poverty levels (OR 2.02, 95% CI 1.50 to 2.70); tuberculosis (TB)/HIV coinfection (OR 1.44, 95% CI 1.19 to 1.74) and educational attainment of grade 12 or more (OR 0.55, 95% CI 0.42 to 0.71). Variables that were not significantly associated with a score of ≥16 included gender, retreatment for TB, positive HIV status of partner and hazardous or harmful alcohol use.
There is a high prevalence of psychological distress among TB patients in South Africa. Older age and greater poverty levels are associated with increased odds, and greater educational attainment is associated with reduced odds of psychological distress.
Notes: The authors note that the K-10 has been shown to capture variability related to non-specific depression and anxiety but that it does not measure suicidality or psychoses. Additionally, the authors note that there is uncertainty regarding the correct K-10 cut-off for South African tuberculosis patients.
Correspondence to: Karl Peltzer, HIV/STI and TB (HAST) Research Programme, Human Sciences Research Council, Pretoria, South Africa; and Department of Psychology, University of the Free State, Bloemfontein, South Africa;
Sources of funding The Department of Health in South Africa.
Peltzer and colleagues used a screening test to examine the prevalence of psychological distress in a large sample of tuberculosis patients seen by public primary-care services in South Africa. The majority of the patients were also HIV positive. The study did not have a control group, but observed what appears to be a high prevalence rate, which varied depending on the cut-off used on the screening test. No data are reported on whether patients were receiving any treatment for this distress, but it is presumed that there is a large unmet need for treatment. The authors recommend improved training for health practitioners in screening, referral and treatment for psychological distress. However, such training would only be useful if there were simple, low-cost interventions which could be feasibly implemented in this healthcare system. This would seem to be a priority for future research.
The authors also examined factors associated with psychological distress within the patient group. Social factors including poverty, low education and not being married were found to increase risk. Because there was no control group, it is unclear whether these factors are specific to the TB patients or whether they are general risk factors for the South African population. From what is known about risk factors for psychological distress in general, it is likely that the association is non-specific. Without a control group, it is also impossible to determine the role of these social factors in contributing to the higher prevalence in the tuberculosis patients. In other words, do the tuberculosis patients have a higher prevalence because they are poorer, less educated or less likely to be married than the general population? Nevertheless, the findings underscore the importance of dealing with social disadvantage in alleviating psychological distress. Providing pharmacological or psychological treatment to patients may not be sufficient to solve the problem. Both clinical and political interventions may be needed.