Research report Symptom Weight loss Herpes zoster Jaundice Vaginal tumours Wasting ARTI Abscesses or sores Oral candidiasis Diarrhoea Recent TB* Table 2 Sensitivity and speciﬁcity of individual signs and symptoms for AIDS deaths in Manicaland and Kisesa cohorts, stratiﬁed at age 45 years Train Test Manicaland phase I 15e44 years (n[237) Se 9 12 19 6 19 11 24 38 17 27 Sp 100 93 93 94 93 95 90 86 95 86 Manicaland phase II 15e59 years (n[102) Se 10 18 4 6 19 10 24 37 17 28 Sp 99 95 97 94 95 95 92 89 92 88 Manicaland phase II 15e44 years (n[180) 45e59 years (n[38) Kisesa 15e44 years (n[158) Se 12 24 4 3 15 8 29 45 29 47 Sp 98 98 100 100 95 95 98 86 93 82 Se 0 19 0 0 13 13 32 26 23 32 Sp 91 100 100 100 100 100 100 91 100 100 Se 10 14 5 0 16 5 19 40 10 5 Sp 96 97 99 100 95 96 96 92 92 99 45e59 years (n[39) Se 23 8 8 0 8 0 8 15 8 8 Sp 84 100 96 96 100 88 100 100 88 96 collect information on herpes zoster, abscesses or sores, vaginal tumours or oral candidiasis (table 3).18 We measured the value of using the ﬁve signs/symptoms that are available from the INDEPTH questionnaire. In the 15e44-year-old age group, using only these ﬁve signs/symptoms resulted in a sensitivity and speciﬁcity of 64% and 82%, respectively (ﬁgure 2). The reduction in sensitivity was less than expected, using the same ﬁve criteria in phase II Manicaland data and earlier Kisesa data sensitivity had decreased to 50% and 44% respectively. DISCUSSION We developed a tool that consistently measures AIDS mortality using verbal autopsy. Through slight modiﬁcation to our previ- ously proposed criteria, the algorithm performs similarly in Zimbabwe and Tanzaniadsettings with different HIV preva- lence (approximately 20% and 7%, respectively9 10) and AIDS mortality and different distribution of other causes of death. The algorithm is robust in that it performs consistently when prev- alence is above approximately 5%. This method of measuring AIDS mortality produced reliable estimates only in the 15e44-year age group. This is due to increasing levels of other-cause mortality in older ages. In Manicaland, where the proportion of deaths due to HIV in the older age groups remained high,11 the methods worked well. But in Kisesa, where HIV prevalence is lower, AIDS mortality begins to drop off after 35 years of age, especially in women.6 14 19 20 and other causes also increase in the 45e59-year age groups. Tuber- culosis, in particular, reduces the speciﬁcity marginally and the sensitivity markedly 21 22 because tuberculosis symptoms overlap substantially with HIV symptoms resulting in misclassiﬁcation. Given the sensitivity and speciﬁcity of the method from the training data, we would predict that 88% and 53% of deaths of 15e44-year-olds in Manicaland and Kisesa were AIDS deaths, respectively. (The formulae for this calculation are described by Lopman et al.12) This compares with directly measured values of 76% and 51%. The overestimate in Manicaland is a result the algorithm actually performing better in phase II (higher speci- ﬁcity) than it did on the training dataset. To calculate the prev- alence of AIDS death, the level of misclassiﬁcation is corrected; however, the level of misclassiﬁcation was actually smaller than calculated on the training data. This approach to estimation of AIDS deaths can be applied to other verbal autopsy data for which a gold standard is not available; however, the accuracy of J Epidemiol Community Health 2010;64:330e334. doi:10.1136/jech.2008.081554 ARTI, acute respiratory tract infections; Se, sensitivity; Sp, speciﬁcity; TB, tuberculosis. *Recent tuberculosis is shown for information but was not included in the ﬁnal algorithm due poor speciﬁcity. Based on this observation, the algorithm was re-trained on Manicaland phase I data, restricted to 15e44-year-olds. This resulted in a different ordering of symptoms compared with the original algorithm and in the inclusion of a ninth symptom since the addition of diarrhoea gave a slightly higher mean sensitivity and speciﬁcity (nine symptoms: 75.1% compared with eight symptoms: 74.7%). Using this new algorithm, a set of nine criteria with a sensitivity of 75.0% and speciﬁcity of 75.2% was produced (ﬁgure 1). The newly trained algorithm performed consistently based on sensitivity and speciﬁcity of data for 15e44-year-olds from Manicaland phase I (sensitivity 79%; sensitivity 79%), Manicaland phase II (sensitivity 83%; speciﬁcity 75%) and Kisesa (sensitivity 75%; speciﬁcity 74%) tests. Although a reasonable speciﬁcity was maintained on 45e59-year-olds, the sensitivity dropped markedly in Manicaland phase I (sensitivity 73%; speciﬁcity 73%), Manica- land phase II (sensitivity 68%; speciﬁcity 80%) and Kisesa (sensi- tivity 54%; speciﬁcity 62%) tests in this older age group (ﬁgure 2). The INDEPTH network is an association of health and DSSs in African, Asian and Oceania countries (http://www. indepth-network.org/). The network has developed a widely used verbal autopsy questionnaire, although the tool does not 0 0 . 1 5 7 . 0 5 2 . 0 y t i tv 0 i isne .05 S Recent TB Diarrhoea Oral candidiasis Jaundice ARTI Abscesses Zoster Wasting Vaginal tumours Weightloss .0 0 . 0 0.00 0.25 0.50 1 - Specificity Area under ROC curve = 0.7697 0.75 1.00 Figure 1 Receiver operator characteristic (ROC) curve of algorithm on deaths of 15e44-year-olds from Manicaland phase I. 332