The death rate among adults in rural Malawi has declined by 10% since the introduction of antiretroviral therapy, and in areas with the highest death rate, it may have declined by up to 35%, according to findings from a London School of Hygiene and Tropical Medicine study published in the May 10th edition of The Lancet.
The study also showed a much higher death rate and lower treatment access among those who lived in more remote areas, suggesting that the chief gap in equity of treatment access is between those who live in rural areas and those who live in larger villages or close to highways, rather than along the lines of gender.
Free antiretroviral therapy began to be introduced in Malawi in 2004 with support from the Global Fund to Fight AIDS, TB and Malaria; by the end of 2006 just over 81,000 people had been enrolled on treatment, a substantial achievement in one of the poorest countries in Africa.
Prior to the introduction of free antiretroviral therapy in Malawi, males aged 15 had a 43% probability of dying before they reached the age of 60, and 63% of the deaths in this age group were attributable to AIDS. Adult HIV prevalence has stabilised around 14% over the past ten years.
Researchers from the London Schoool of Hygiene and Tropical Medicine evaluated the impact of antiretroviral therapy on mortality in the northern district of Karonga, on the shores of Lake Malawi. The study utilised demographic data collected in the Karonga prevention study, a door-to-door census in 2002, and information on mortality from 230 population clusters followed up between 2004 and 2006.
Causes of death were established with a semi-structured questionnaire administered by a health assistant whenever a death occurred in each of the population clusters, which numbered 15-60 households each. Questionnaire results were then reviewed by three doctors and clinical officers to determine the most likely underlying cause of death.
Antiretroviral therapy in the district became available in 2005 with the opening of a free clinic.
Results
Between 2002 and 2006, 916 deaths were recorded among a total population of 39,321 individuals followed for a total of 81,278 person-years. In adults aged 15-59 the death rate was 9.8 per 1000 person-years. Sixty-five per cent of deaths in this age group were attributable to AIDS, and 60% of AIDS deaths were in women. Prior to the introduction of antiretroviral therapy the probability of death in the 15-59 age group was 43%, and the lifetime risk of death from AIDS for a child born in the study district was 37%.
After the introduction of antiretroviral therapy all-cause mortality declined by 10% in those aged 15-59, and AIDS-related mortality declined by 19% (95% confidence interval 0.58 – 1.12). There was no corresponding decline in mortality in those aged 60 and over.
The decline in AIDS-related mortality was greatest in those who lived within 1km of the tarmac road running north-south through the district. AIDS-related mortality had also been higher in this area prior to the introduction of antiretroviral therapy (RR 1.91, 95% CI 1.49-2.48). All-cause mortality fell by 35% and AIDS-related mortality by 33% in this zone among those aged 15-59 (RR 0.65, 95% CI 0.46-0.92, and RR 0.67, 95% CI 0.44 -1.03 respectively).
Among those who lived in more remote areas there was almost no change in AIDS-related mortality after the introduction of antiretroviral therapy. Of those who started treatment, 73% lived within 1km of the road. The authors estimate that around a third of those in the district who needed treatment were obtaining it, and the $3 cost of transport to the clinic may have been a substantial impediment. The monthly average income was estimated at $23 in 2004.
Ninety-nine adults started antiretroviral therapy during the eight months it was available in the distric, and twelve died after starting treatment; a further eight deaths were identified in adults who had obtained antiretroviral treatment outside the district. Overall 8% of AIDS deaths occurred in those who received ART, and data from the Malawian Ministry of Health’s monitoring of the treatment programme showed that at the Karonga clinic the risk of death was 25% in the first six months after starting treatment. Only 19% of AIDS deaths occurred more than three months after treatment started.
The authors acknowledge that the sensitivity and specificity of the `verbal autopsy` method used in this study in which a health assistant questioned the relatives of the deceased about the cause of death, is lower than attribution of cause of death based on HIV status. However information about HIV status became more common after the introduction of antiretroviral therapy; 30% of those who died in the area near the road had been tested for HIV after treatment became available, compared to 19% previously.
Although not all reductions in mortality were statistically significant, the findings nevertheless show, say the authors, that AIDS deaths can be averted by the rapid scale-up of antiretroviral therapy in resource-limited settings.
Jahn A et al. Population-level effect of HIV on adult mortality and early evidence of reversal after introduction of antiretroviral therapy in Malawi. The Lancet 371: 1603-1611, 2008.