Between August, 2002, and the end of February, 2006, we recorded 916 deaths in 39 321 individuals during 81 278 person-years of observation, which equates to a crude death rate of 11 per 1000 per year (95% CI 10·6–12·0) and an age-standardised death rate of 12 per 1000 person-years of observation. Of these deaths, 574 were in adults older than 14 years (for whom we recorded 42 657 person-years of observation), and 373 deaths were in 18 927 adults aged 15–59 years (with 38 015 person-years of observation). Therefore, the adult mortality rate was 9·8 per 1000 person-years of observation (95% CI 8·9–10·9), with 9·6 (8·3–11·1) in men and 10·0 (8·6–11·5) in women.
269 (46·9%) of the 574 deaths in adults older than 14 years occurred at health facilities, 262 (45·6%) at home, 30 (5·2%) outdoors, and 13 (2·3%) at traditional healer camps. shows the probable causes for these 574 deaths. Verbal autopsies were available for 570 (99·3%), and a probable cause was established for 509 deaths (227 [88%] of men and 282 [89%] of women). More female than male deaths were attributed to AIDS: 145 (51%) of 282 women died of AIDS, compared with 98 (43%) of 227 men (p=0·065).
Probable causes of death in 574 adults aged older than 14 years
Of the 373 deaths in adults aged 15–59 years, verbal autopsies were available for 372 (99·4%). In this age-group, probable causes were established for 352 deaths (159 [91·4%] of deaths in men and 192 [96·5%] in women). 229 (65·1%) of these 352 deaths were attributed to AIDS. 139 (72·0%) women and 90 (56·6%) men died of AIDS—ie, 60·7% of all AIDS deaths were in women.
Mortality rates from all causes by sex and age in the period before antiretroviral therapy was introduced in June 2005 are shown in . Death rates initially peaked between the ages of 40 and 44 years for both men and women, and then rose again at later ages. Death rates increased at an earlier age in women than in men; and were 3·4 times higher (95% CI 1·3–8·9) at age 20–24 years (adjusted for area). This differential was lost by the ages of 30–34 years, and at older ages rates of death in women were slightly lower than in men. also shows age-specific and sex-specific mortality from AIDS and from all other causes combined for the same period; the high mortality in young women and the peak between the ages of 40 and 44 years is clearly attributable to AIDS. Overall adult mortality from all causes was almost identical in women and men (rate ratio [RR] adjusted for age and area 0·97, 95% CI 0·81–1·17), but AIDS-specific mortality was higher in women (RR adjusted for age and area 1·36, 1·01–1·82). The overall age-standardised AIDS mortality rate in adults older than 14 years was 6·3 deaths per 1000 person-years of observation, with 4·9 in men and 6·5 in women.
Mortality rates by sex and age-group before availability of antiretroviral therapy
and show survival probability by age and adult mortality risks in the period before antiretroviral therapy. Before the opening of the Karonga clinic, the probability of dying from any cause between the exact ages of 15 and 60 years (45q15, adjusted for area) was 43% (95% CI 39–49) for men and 43% (38–47) for women. Of the 289 deaths in adults aged 15–59 years in this period, 181 (63%) were attributed to AIDS. The probability of dying of any cause other than AIDS between ages 15 and 60 years (45q15, adjusted for area) was 19% (95% CI 15–25) for men and 15% (12–20) for women. Two other measures for the probability of dying are shown in to allow comparison with other studies. Assuming unchanged HIV-incidence and mortality, a child born into the surveillance population before the introduction of antiretroviral therapy would have had a 37% lifetime risk of dying from AIDS (35% for boys and 38% for girls).
Kaplan–Meier survival function for the entire study population before introduction of antiretroviral therapy
Probability of dying between the ages of 15 and 60, 20 and 50, and 30 and 65 years in the surveillance population before opening of the antiretroviral therapy clinic in June, 2005, adjusted for area
Overall mortality rates before and after opening of the antiretroviral therapy clinic in Karonga district are shown in . After the opening of the clinic, all-cause mortality in adults aged 15–59 years decreased by 10% (the rate ratio [RR] adjusted for age, sex, and area was 0·90, 95% CI 0·70–1·15), which is equivalent to nine deaths averted in the 8-month observation period after introduction of antiretroviral therapy. All-cause mortality in individuals aged 60 years and older did not change. AIDS mortality decreased by 19% in the 15–59-year age-group (adjusted RR 0·81, 0·58–1·12), with no change in mortality from causes other than AIDS.
Trends in adult mortality before and after opening of the antiretroviral clinic in Karonga district
Trends in adult mortality differed in the two zones that were defined according to distance from the tarmac road (p=0·003, test for interaction in adults aged 15–59 years). Mortality in adults aged 15–59 years before the introduction of antiretroviral therapy was much higher in the 1 km zone close to the tarmac roads than in the rest of the study area (rate ratio [RR] 1·91, 95% CI 1·49–2·48). shows that the mortality rate was reduced by 35% in adults aged 15–59 years who lived within 1 km of the tarmac roads (RR adjusted for age and area 0·65, 0·46–0·92) after the opening of the antiretroviral therapy clinic. Reductions were seen in each of the age-groups, 15–29, 30–44, and 45–59 years. In the zone further away from the road, mortality increased slightly in those aged 15–59 years. Mortality rates in adults aged 60 years or older did not change in either zone (area-adjusted RR: 1 km-zone 0·99, remote zone 1·03).
In the zone within 1 km of the tarmac roads, AIDS mortality in adults aged 15–59 years was reduced by 33% after the opening of the Karonga antiretroviral therapy clinic (rate ratio [RR], adjusted for age, sex, and area 0·67, 95% CI 0·44–1·03) and little change was seen in the more remote zone (RR, adjusted for age, sex, and area 1·07, 0·64–1·79). Deaths that were classified as not related to AIDS also decreased close to the road (RR adjusted for age, sex, and area 0·57, 0·30–1·10), but increased further from the road (RR adjusted for age, sex, and area 2·36, 1·32–4·20). 11 men and 12 women died of causes other than AIDS in the remote zone after the introduction of antiretroviral therapy (five from gastrointestinal causes, four cardiovascular, four cancer, three meningitis, three accidents, two from tuberculosis, and one maternal death). Of adults aged 15–59 years who died, three had moved from the near zone to the more remote zone and two in the other direction before the introduction of antiretroviral therapy. After the clinic opened, three moved from the near to the more remote zone.
By the end of the observation period, in February, 2006, 99 adults from the study population had accessed antiretroviral therapy at the Karonga clinic and 12 of these (seven women and five men) died during the observation period. The verbal autopsies revealed that an additional eight adults (five women and three men) had received antiretroviral therapy before their death, but had not been identified at the Karonga clinic and therefore apparently received treatment from another source, some probably before the opening of the Karonga clinic in June, 2005. Overall 12 women and eight men who had antiretroviral therapy died during the observation period (accounting for 8% of AIDS deaths).
Of all 107 adults (74 women and 33 men) known to have accessed antiretroviral therapy, 78 (73%) lived within 1 km of the tarmac roads. The rate of access per person-years of observation in people near the road was 2·6 times that in the more distant zone (p<0·0001).