Agreement between cause of death assignment by computer-coded verbal autopsy methods and physician coding of verbal autopsy interviews in South Africa

BACKGROUND

The South African national cause of death validation (NCODV 2017/18) project collected a national sample of verbal autopsies (VA) with cause of death (COD) assignment by physician-coded VA (PCVA) and computer-coded VA (CCVA).

OBJECTIVE

The performance of three CCVA algorithms (InterVA-5, InSilicoVA and Tariff 2.0) in assigning a COD was compared with PCVA (reference standard).

METHODS

Seven performance metrics assessed individual and population level agreement of COD assignment by age, sex and place of death subgroups. Positive predictive value (PPV), sensitivity, overall agreement, kappa, and chance corrected concordance (CCC) assessed individual level agreement. Cause-specific mortality fraction (CSMF) accuracy and Spearman's rank correlation assessed population level agreement.

RESULTS

A total of 5386 VA records were analysed. PCVA and CCVAs all identified HIV/AIDS as the leading COD. CCVA PPV and sensitivity, based on confidence intervals, were comparable except for HIV/AIDS, TB, maternal, diabetes mellitus, other cancers, and some injuries. CCVAs performed well for identifying perinatal deaths, road traffic accidents, suicide and homicide but poorly for pneumonia, other infectious diseases and renal failure. Overall agreement between CCVAs and PCVA for the top single cause (48.2-51.6) indicated comparable weak agreement between methods. Overall agreement, for the top three causes showed moderate agreement for InterVA (70.9) and InSilicoVA (73.8). Agreement based on kappa (-0.05-0.49)and CCC (0.06-0.43) was weak to none for all algorithms and groups. CCVAs had moderate to strong agreement for CSMF accuracy, with InterVA-5 highest for neonates (0.90), Tariff 2.0 highest for adults (0.89) and males (0.84), and InSilicoVA highest for females (0.88), elders (0.83) and out-of-facility deaths (0.85). Rank correlation indicated moderate agreement for adults (0.75-0.79).

CONCLUSIONS

Whilst CCVAs identified HIV/AIDS as the leading COD, consistent with PCVA, there is scope for improving the algorithms for use in South Africa.

Further evidence of misclassification of the injury deaths in South Africa: When will the barriers to accurate injury death statistics be removed?

BACKGROUND

Contrary to the World Health Organization's internationally recommended medical certificate of cause of death, the South African (SA) death notification form (DNF) does not allow for the reporting of the manner of death to permit accurate coding of external causes of injury deaths.

OBJECTIVES

To describe the injury cause-of-death profile from forensic pathology records collected for the National Cause-of-Death Validation (NCoDV) Project and compare it with profiles from other sources of injury mortality data. In particular, the recording of firearm use in homicides is compared between sources.

METHODS

The NCoDV Project was a cross-sectional study of deaths that occurred during a fixed period in 2017 and 2018, from a nationally representative sample of 27 health subdistricts in SA. Trained fieldworkers scanned forensic records for all deaths investigated at the forensic mortuaries serving the sampled subdistricts during the study period. Forensic practitioners reviewed the records and completed a medical certificate of cause of death for each decedent. Causes of death were coded to the International Statistical Classification of Diseases, 10th revision (ICD-10), using Iris automated coding software. Cause-specific mortality fractions for injury deaths were compared with Injury Mortality Survey 2017 (IMS 2017) and Statistics South Africa 2017 (Stats SA 2017) datasets. The cause profile for all firearm-related deaths was compared between the three datasets.

RESULTS

A total of 5 315 records were available for analysis. Males accounted for 77.6% of cases, and most decedents were aged between 25 and 44 years. Homicide was the leading cause of death (34.7%), followed by transport injuries (32.6%) and suicide (14.7%). This injury cause profile was similar to IMS 2017 but differed markedly from the official statistics, which showed markedly lower proportions of these three causes (15.0%, 11.6% and 0.7%, respectively), and a much higher proportion of other unintentional causes. Investigation of firearm-related deaths revealed that most were homicides in NCoDV 2017/18 (88.5%) and IMS 2017 (93.1%), while in the Stats SA 2017 data, 98.7% of firearm deaths were classified as accidental. Approximately 7% of firearm-related deaths were suicides in NCoDV 2017/18 and IMS 2017, with only 0.3% in Stats SA 2017.

CONCLUSION

The official cause-of-death data for injuries in SA in 2017 differed substantially from findings from the NCoDV 2017/18 study and IMS 2017. Accurate data sources would ensure that public health interventions are designed to reduce the high injury burden. Inclusion of the manner of death on the DNF, as is recommended internationally, is critically important to enable more accurate, reliable and valid reporting of the injury profile.

The importance of including manner of (injury) death on the death notification form

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Risk Factors for Coronavirus Disease 2019 (COVID-19) Death in a Population Cohort Study from the Western Cape Province, South Africa

BACKGROUND

Risk factors for coronavirus disease 2019 (COVID-19) death in sub-Saharan Africa and the effects of human immunodeficiency virus (HIV) and tuberculosis on COVID-19 outcomes are unknown.

METHODS

We conducted a population cohort study using linked data from adults attending public-sector health facilities in the Western Cape, South Africa. We used Cox proportional hazards models, adjusted for age, sex, location, and comorbidities, to examine the associations between HIV, tuberculosis, and COVID-19 death from 1 March to 9 June 2020 among (1) public-sector "active patients" (≥1 visit in the 3 years before March 2020); (2) laboratory-diagnosed COVID-19 cases; and (3) hospitalized COVID-19 cases. We calculated the standardized mortality ratio (SMR) for COVID-19, comparing adults living with and without HIV using modeled population estimates.

RESULTS

Among 3 460 932 patients (16% living with HIV), 22 308 were diagnosed with COVID-19, of whom 625 died. COVID-19 death was associated with male sex, increasing age, diabetes, hypertension, and chronic kidney disease. HIV was associated with COVID-19 mortality (adjusted hazard ratio [aHR], 2.14; 95% confidence interval [CI], 1.70-2.70), with similar risks across strata of viral loads and immunosuppression. Current and previous diagnoses of tuberculosis were associated with COVID-19 death (aHR, 2.70 [95% CI, 1.81-4.04] and 1.51 [95% CI, 1.18-1.93], respectively). The SMR for COVID-19 death associated with HIV was 2.39 (95% CI, 1.96-2.86); population attributable fraction 8.5% (95% CI, 6.1-11.1).

CONCLUSIONS

While our findings may overestimate HIV- and tuberculosis-associated COVID-19 mortality risks due to residual confounding, both living with HIV and having current tuberculosis were independently associated with increased COVID-19 mortality. The associations between age, sex, and other comorbidities and COVID-19 mortality were similar to those in other settings.

COVID deaths in South Africa: 99 days since South Africa's first death

BACKGROUND

Understanding the pattern of deaths from COVID-19 in South Africa (SA) is critical to identifying individuals at high risk of dying from the disease. The Minister of Health set up a daily reporting mechanism to obtain timeous details of COVID-19 deaths from the provinces to track mortality patterns.

OBJECTIVES

To provide an epidemiological analysis of the first COVID-19 deaths in SA.

METHODS

Provincial deaths data from 28 March to 3 July 2020 were cleaned, information on comorbidities was standardised, and data were aggregated into a single data set. Analysis was performed by age, sex, province, date of death and comorbidities.

RESULTS

SA reported 3 088 deaths from COVID-19, i.e. an age-standardised death rate of 64.5 (95% confidence interval (CI) 62.3 - 66.8) deaths per million population. Most deaths occurred in Western Cape (65.5%) followed by Eastern Cape (16.8%) and Gauteng (11.3%). The median age of death was 61 years (interquartile range 52 - 71). Males had a 1.5 times higher death rate compared with females. Individuals with two or more comorbidities accounted for 58.6% (95% CI 56.6 - 60.5) of deaths. Hypertension and diabetes were the most common comorbidities reported, and HIV and tuberculosis were more common in individuals aged <50 years.

CONCLUSIONS

Data collection for COVID-19 deaths in provinces must be standardised. Even though the data had limitations, these findings can be used by the SA government to manage the pandemic and identify individuals who are at high risk of dying from COVID-19.

Mortality trends and differentials in South Africa from 1997 to 2012: second National Burden of Disease Study

BACKGROUND

The poor health of South Africans is known to be associated with a quadruple disease burden. In the second National Burden of Disease (NBD) study, we aimed to analyse cause of death data for 1997-2012 and develop national, population group, and provincial estimates of the levels and causes of mortality.

METHOD

We used underlying cause of death data from death notifications for 1997-2012 obtained from Statistics South Africa. These data were adjusted for completeness using indirect demographic techniques for adults and comparison with survey and census estimates for child mortality. A regression approach was used to estimate misclassified HIV/AIDS deaths and so-called garbage codes were proportionally redistributed by age, sex, and population group population group (black African, Indian or Asian descent, white [European descent], and coloured [of mixed ancestry according to the preceding categories]). Injury deaths were estimated from additional data sources. Age-standardised death rates were calculated with mid-year population estimates and the WHO age standard. Institute of Health Metrics and Evaluation Global Burden of Disease (IHME GBD) estimates for South Africa were obtained from the IHME GHDx website for comparison.

FINDINGS

All-cause age-standardised death rates increased rapidly since 1997, peaked in 2006 and then declined, driven by changes in HIV/AIDS. Mortality from tuberculosis, non-communicable diseases, and injuries decreased slightly. In 2012, HIV/AIDS caused the most deaths (29·1%) followed by cerebrovascular disease (7·5%) and lower respiratory infections (4·9%). All-cause age-standardised death rates were 1·7 times higher in the province with the highest death rate compared to the province with the lowest death rate, 2·2 times higher in black Africans compared to whites, and 1·4 times higher in males compared with females. Comparison with the IHME GBD estimates for South Africa revealed substantial differences for estimated deaths from all causes, particularly HIV/AIDS and interpersonal violence.

INTERPRETATION

This study shows the reversal of HIV/AIDS, non-communicable disease, and injury mortality trends in South Africa during the study period. Mortality differentials show the importance of social determinants, raise concerns about the quality of health services, and provide relevant information to policy makers for addressing inequalities. Differences between GBD estimates for South Africa and this study emphasise the need for more careful calibration of global models with local data.

FUNDING

South African Medical Research Council's Flagships Awards Project.

Epidemiology of lower respiratory infection and pneumonia in South Africa (1997-2015): a systematic review protocol

INTRODUCTION

Lower respiratory infections (LRIs) and pneumonia are among the leading causes of death worldwide, especially in children aged under 5 years, and these patterns are reflected in the South African population. Local epidemiological data for LRIs and pneumonia are required to inform the Second National Burden of Disease Study underway in South Africa. The aim of this systematic review is to identify published studies reporting the prevalence, incidence, case fatality, duration or severity of LRI and pneumonia in adults and children in South Africa.

METHODS AND ANALYSIS

Electronic database searches will be conducted to obtain studies reporting on the prevalence, incidence, case fatality, duration and severity of LRI and pneumonia in South Africa between January 1997 and December 2015. Studies that are assessed to have moderate or low risk of bias will be included in a meta-analysis, if appropriate. Where meta-analysis is not possible, the articles will be described narratively. Subgroup analysis (eg, age groups) will also be conducted where enough information is available.

ETHICS AND DISSEMINATION

This systematic review will only include published data with no linked patient-level information; thus, no ethics approval is required. The findings will be used to calculate the burden of disease attributed to LRI and pneumonia in South Africa and will highlight the type of epidemiological data available in the country. The article will be disseminated in a peer-reviewed publication.

PROSPERO REGISTRATION NUMBER

CRD42016036520.

Linking mortuary data improves vital statistics on cause of death of children under five years in the Western Cape Province of South Africa

OBJECTIVES

Reducing child mortality requires good information on its causes. Whilst South African vital registration data have improved, the quality of cause-of-death data remains inadequate. To improve this, data from death certificates were linked with information from forensic mortuaries in Western Cape Province.

METHODS

A local mortality surveillance system was established in 2007 by the Western Cape Health Department to improve data quality. Cause-of-death data were captured from copies of death notification forms collected at Department of Home Affairs Offices. Using unique identifiers, additional forensic mortuary data were linked with mortality surveillance system records. Causes of death were coded to the ICD-10 classification. Causes of death in children under five were compared with those from vital registration data for 2011.

RESULTS

Cause-of-death data were markedly improved with additional data from forensic mortuaries. The proportion of ill-defined causes was halved (25-12%), and leading cause rankings changed. Lower respiratory tract infections moved above prematurity to rank first, accounting for 20.8% of deaths and peaking in infants aged 1-3 months. Only 11% of deaths from lower respiratory tract infections occurred in hospital, resulting in 86% being certified in forensic mortuaries. Road traffic deaths increased from 1.1-3.1% (27-75) and homicides from 3 to 28.

CONCLUSIONS

The quality and usefulness of cause-of-death information for children in the WC was enhanced by linking mortuary and vital registration data. Given the death profile, interventions are required to prevent and manage LRTI, diarrhoea and injuries and to reduce neonatal deaths.

Differences among the coloured, white, black, and other South African populations in smoking-attributed mortality at ages 35-74 years: a case-control study of 481,640 deaths

BACKGROUND

The full eventual effects of current smoking patterns cannot yet be seen in Africa. In South Africa, however, men and women in the coloured (mixed black and white ancestry) population have smoked for many decades. We assess mortality from smoking in the coloured, white, and black (African) population groups.

METHODS

In this case-control study, 481,640 South African notifications of death at ages 35-74 years between 1999 and 2007 yielded information about age, sex, population group, education, smoking 5 years ago (yes or no), and underlying disease. Cases were deaths from diseases expected to be affected by smoking; controls were deaths from selected other diseases, excluding only HIV, cirrhosis, unknown causes, external causes, and mental disorders. Disease-specific case-control comparisons yielded smoking-associated relative risks (RRs; diluted by combining some ex-smokers with the never-smokers). These RRs, when combined with national mortality rates, yielded smoking-attributed mortality rates. Summation yielded RRs and smoking-attributed numbers for overall mortality.

FINDINGS

In the coloured population, smoking prevalence was high in both sexes and smokers had about 50% higher overall mortality than did otherwise similar non-smokers or ex-smokers (men, RR 1·55, 95% CI 1·43-1·67; women, 1·49, 1·38-1·60). RRs were similar in the white population (men, 1·37, 1·29-1·46; women, 1·51, 1·40-1·62), but lower among Africans (men, 1·17, 1·15-1·19; women, 1·16, 1·13-1·20). If these associations are largely causal, smoking-attributed proportions for overall male deaths at ages 35-74 years were 27% (5608/20,767) in the coloured, 14% (3913/28,951) in the white, and 8% (20,398/264,011) in the African population. For female deaths, these proportions were 17% (2728/15,593) in the coloured, 12% (2084/17,899) in the white, and 2% (4038/205,623) in the African population. Because national mortality rates were also substantially higher in the coloured than in the white population, the hazards from smoking in the coloured population were more than double those in the white population.

INTERPRETATION

The highest smoking-attributed mortality rates were in the coloured population and the lowest were in Africans. The substantial hazards already seen among coloured South Africans suggest growing hazards in all populations in Africa where young adults now smoke.

FUNDING

South African Medical Research Council, UK Medical Research Council, Cancer Research UK, British Heart Foundation, New South Wales Cancer Council.

Local-level mortality surveillance in resource-limited settings: a case study of Cape Town highlights disparities in health

OBJECTIVE

To identify the leading causes of mortality and premature mortality in Cape Town, South Africa, and its subdistricts, and to compare levels of mortality between subdistricts.

METHODS

Cape Town mortality data for the period 2001-2006 were analysed by age, cause of death and sex. Cause-of-death codes were aggregated into three main cause groups: (i) pre-transitional causes (e.g. communicable diseases, maternal causes, perinatal conditions and nutritional deficiencies), (ii) noncommunicable diseases and (iii) injuries. Premature mortality was calculated in years of life lost (YLLs). Population estimates for the Cape Town Metro district were used to calculate age-specific rates per 100,000 population, which were then age-standardized and compared across subdistricts.

FINDINGS

The pattern of mortality in Cape Town reflects the quadruple burden of disease observed in the national cause-of-death profile, with HIV/AIDS, other infectious diseases, injuries and noncommunicable diseases all accounting for a significant proportion of deaths. HIV/AIDS has replaced homicide as the leading cause of death. HIV/AIDS, homicide, tuberculosis and road traffic injuries accounted for 44% of all premature mortality. Khayelitsha, the poorest subdistrict, had the highest levels of mortality for all main cause groups.

CONCLUSION

Local mortality surveillance highlights the differential needs of the population of Cape Town and provides a wealth of data to inform planning and implementation of targeted interventions. Multisectoral interventions will be required to reduce the burden of disease.

Quality of cause of death certification at an academic hospital in Cape Town, South Africa

OBJECTIVES

To investigate the quality of cause of death certification and assess the level of under-reporting of HIV/AIDS as a cause of death at an academic hospital.

DESIGN

Cross-sectional descriptive retrospective review of death notification forms (DNFs) of deaths due to natural causes in an academic hospital in Cape Town during 2004. Errors in cause of death certification and ability to code causes of death according to the 10th revision of the International Statistical Classification of Diseases and Related Health Problems (ICD-10) were assessed. The association between serious errors and age, gender, cause of death and hospital ward was analysed. A sample of DNFs (N=243) was assessed for level of under-reporting of HIV/AIDS.

RESULTS

A total of 983 death certificates were evaluated. Almost every DNF had a minor error; serious errors were found in 32.2% (95% confidence interval (CI) 29.3-35.1%). Errors increased with patient age, and cause of death was the most important factor associated with serious errors. Compared with neoplasms, which had the lowest error rate, the odds ratios for errors in endocrine and metabolic diseases and genito-urinary diseases were 17.2 (95% CI 8.7-34.0) and 17.3 (95% CI 7.8-38.2), respectively. Based on the sub-sample, the minimum prevalence of HIV among the deceased patients was 15.7% (95% CI 11.1-20.3%) and the under-reporting of deaths due to AIDS was 53.1% (95% CI 35.8-70.4%).

CONCLUSION

Errors were sufficiently serious to affect identification of underlying cause of death in almost a third of the DNFs, confirming the need to improve the quality of medical certification.

The high burden of injuries in South Africa

OBJECTIVE

To estimate the magnitude and characteristics of the injury burden in South Africa within a global context.

METHODS

The Actuarial Society of South Africa demographic and AIDS model (ASSA 2002) - calibrated to survey, census and adjusted vital registration data - was used to calculate the total number of deaths in 2000. Causes of death were determined from the National Injury Mortality Surveillance System profile. Injury death rates and years of life lost (YLL) were estimated using the Global Burden of Disease methodology. National years lived with disability (YLDs) were calculated by applying a ratio between YLLs and YLDs found in a local injury data source, the Cape Metropole Study. Mortality and disability-adjusted life years' (DALYs) rates were compared with African and global estimates.

FINDINGS

Interpersonal violence dominated the South African injury profile with age-standardized mortality rates at seven times the global rate. Injuries were the second-leading cause of loss of healthy life, accounting for 14.3% of all DALYs in South Africa in 2000. Road traffic injuries (RTIs) are the leading cause of injury in most regions of the world but South Africa has exceedingly high numbers - double the global rate.

CONCLUSION

Injuries are an important public health issue in South Africa. Social and economic determinants of violence, many a legacy of apartheid policies, must be addressed to reduce inequalities in society and build community cohesion. Multisectoral interventions to reduce traffic injuries are also needed. We highlight this heavy burden to stress the need for effective prevention programmes.

Estimating the burden of disease attributable to smoking in South Africa in 2000

OBJECTIVES

To quantify the burden of disease attributable to smoking in South Africa for 2000.

DESIGN

The absolute difference between observed lung cancer death rate and the level in non-smokers, adjusted for occupational and indoor exposure to lung carcinogens, was used to estimate the proportion of lung cancer deaths attributable to smoking and the smoking impact ratio (SIR). The SIR was substituted for smoking prevalence in the attributable fraction formula for chronic obstructive pulmonary disease (COPD) and cancers to allow for the long lag between exposure and outcome. Assuming a shorter lag between exposure and disease, the current prevalence of smoking was used to estimate the population-attributable fractions (PAF) for the other outcomes. Relative risks (RR) from the American Cancer Society cancer prevention study (CPS-II) were used to calculate PAF.

SETTING

South Africa.

OUTCOME MEASURES

Deaths and disability-adjusted life years (DALYs) due to lung and other cancers, COPD, cardiovascular conditions, respiratory tuberculosis, and other respiratory and medical conditions.

RESULTS

Smoking caused between 41,632 and 46,656 deaths in South Africa, accounting for 8.0 - 9.0% of deaths and 3.7 - 4.3% of DALYs in 2000. Smoking ranked third (after unsafe sex/ sexually transmitted disease and high blood pressure) in terms of mortality among 17 risk factors evaluated. Three times as many males as females died from smoking. Lung cancer had the largest attributable fraction due to smoking. However, cardiovascular diseases accounted for the largest proportion of deaths attributed to smoking.

CONCLUSION

Cigarette smoking accounts for a large burden of preventable disease in South Africa. While the government has taken bold legislative action to discourage tobacco use since 1994, it still remains a major public health priority.

Estimating the burden of disease attributable to physical inactivity in South Africa in 2000

OBJECTIVES

To quantify the burden of disease attributable to physical inactivity in persons 15 years or older, by age group and sex, in South Africa for 2000.

DESIGN

The global comparative risk assessment (CRA) methodology of the World Health Organization was followed to estimate the disease burden attributable to physical inactivity. Levels of physical activity for South Africa were obtained from the World Health Survey 2003. A theoretical minimum risk exposure of zero, associated outcomes, relative risks, and revised burden of disease estimates were used to calculate population-attributable fractions and the burden attributed to physical inactivity. Monte Carlo simulation-modelling techniques were used for the uncertainty analysis.

SETTING

South Africa.

SUBJECTS

Adults >or= 15 years.

OUTCOME MEASURES

Deaths and disability-adjusted life years (DALYs) from ischaemic heart disease, ischaemic stroke, breast cancer, colon cancer, and type 2 diabetes mellitus.

RESULTS

Overall in adults >or= 15 years in 2000, 30% of ischaemic heart disease, 27% of colon cancer, 22% of ischaemic stroke, 20% of type 2 diabetes, and 17% of breast cancer were attributable to physical inactivity. Physical inactivity was estimated to have caused 17,037 (95% uncertainty interval 11,394 - 20,407), or 3.3% (95% uncertainty interval 2.2 - 3.9%) of all deaths in 2000, and 176,252 (95% uncertainty interval 133,733 - 203,628) DALYs, or 1.1% (95% uncertainty interval 0.8 - 1.3%) of all DALYs in 2000.

CONCLUSIONS

Compared with other regions and the global average, South African adults have a particularly high prevalence of physical inactivity. In terms of attributable deaths, physical inactivity ranked 9th compared with other risk factors, and 12th in terms of DALYs. There is a clear need to assess why South Africans are particularly inactive, and to ensure that physical activity/inactivity is addressed as a national health priority.

Provincial mortality in South Africa, 2000--priority-setting for now and a benchmark for the future

BACKGROUND

Cause-of-death statistics are an essential component of health information. Despite improvements, underregistration and misclassification of causes make it difficult to interpret the official death statistics.

OBJECTIVE

To estimate consistent cause-specific death rates for the year 2000 and to identify the leading causes of death and premature mortality in the provinces.

METHODS

Total number of deaths and population size were estimated using the Actuarial Society of South Africa ASSA2000 AIDS and demographic model. Cause-of-death profiles based on Statistics South Africa's 15% sample, adjusted for misclassification of deaths due to ill-defined causes and AIDS deaths due to indicator conditions, were applied to the total deaths by age and sex. Age-standardised rates and years of life lost were calculated using age weighting and discounting.

RESULTS

Life expectancy in KwaZulu-Natal and Mpumalanga is about 10 years lower than that in the Western Cape, the province with the lowest mortality rate. HIV/AIDS is the leading cause of premature mortality for all provinces. Mortality due to pre-transitional causes, such as diarrhoea, is more pronounced in the poorer and more rural provinces. In contrast, non-communicable disease mortality is similar across all provinces, although the cause profiles differ. Injury mortality rates are particularly high in provinces with large metropolitan areas and in Mpumalanga.

CONCLUSION

The quadruple burden experienced in all provinces requires a broad range of interventions, including improved access to health care; ensuring that basic needs such as those related to water and sanitation are met; disease and injury prevention; and promotion of a healthy lifestyle. High death rates as a result of HIV/AIDS highlight the urgent need to accelerate the implementation of the treatment and prevention plan. In addition, there is an urgent need to improve the cause-of-death data system to provide reliable cause-of-death statistics at health district level.

Identifying deaths from AIDS in South Africa

OBJECTIVE

To quantify the HIV/AIDS deaths misclassified to AIDS-related conditions in South Africa.

DESIGN

Retrospective analysis of vital registration data.

METHODS

Cause-specific death rates for 1996 and 2000-2001 were calculated using vital registration cause-of-death profiles applied to a model (ASSA2000) estimate of total mortality rates by age and sex. The difference in the age-specific death rates for these two periods was examined to identify conditions where there was a noticeable increase in mortality following the same age pattern as the HIV deaths, thus likely to be misclassified AIDS deaths.

RESULTS

The increase in the age-specific death rates for HIV-related deaths showed a distinct age pattern, which has been observed elsewhere. Out of the 22 potential causes of death investigated, there were nine that increased in the same distinct age pattern (tuberculosis, pneumonia, diarrhoea, meningitis, other respiratory disease, non-infective gastroenteritis, other infectious and parasitic diseases, deficiency anaemias and protein energy malnutrition) and could be considered AIDS-related conditions. The increase in these conditions accounted for 61% of the total deaths related to HIV/AIDS. When added to the deaths classified as HIV-related on the death certificate, the total accounts for 93% of the ASSA2000 model estimates of the number of AIDS deaths in 2000.

CONCLUSION

As a large proportion of AIDS deaths appear to be classified to AIDS-related conditions, without reference to HIV, interpretation of death statistics in South Africa cannot be made on face value as a large proportion of deaths caused by HIV infection are misclassified.

Initial burden of disease estimates for South Africa, 2000

BACKGROUND

This paper describes the first national burden of disease study for South Africa. The main focus is the burden due to premature mortality, i.e. years of life lost (YLLs). In addition, estimates of the burden contributed by morbidity, i.e. the years lived with disability (YLDs), are obtained to calculate disability-adjusted life years (DALYs); and the impact of AIDS on premature mortality in the year 2010 is assessed.

METHOD

Owing to the rapid mortality transition and the lack of timely data, a modelling approach has been adopted. The total mortality for the year 2000 is estimated using a demographic and AIDS model. The non-AIDS cause-of-death profile is estimated using three sources of data: Statistics South Africa, the National Department of Home Affairs, and the National Injury Mortality Surveillance System. A ratio method is used to estimate the YLDs from the YLL estimates.

RESULTS

The top single cause of mortality burden was HIV/AIDS followed by homicide, tuberculosis, road traffic accidents and diarrhoea. HIV/AIDS accounted for 38% of total YLLs, which is proportionately higher for females (47%) than for males (33%). Pre-transitional diseases, usually associated with poverty and underdevelopment, accounted for 25%, non-communicable diseases 21% and injuries 16% of YLLs. The DALY estimates highlight the fact that mortality alone underestimates the burden of disease, especially with regard to unintentional injuries, respiratory disease, and nervous system, mental and sense organ disorders. The impact of HIV/AIDS is expected to more than double the burden of premature mortality by the year 2010.

CONCLUSION

This study has drawn together data from a range of sources to develop coherent estimates of premature mortality by cause. South Africa is experiencing a quadruple burden of disease comprising the pre-transitional diseases, the emerging chronic diseases, injuries, and HIV/AIDS. Unless interventions that reduce morbidity and delay morbidity become widely available, the burden due to HIV/AIDS can be expected to grow very rapidly in the next few years. An improved base of information is needed to assess the morbidity impact more accurately.

The 5-year outcome of multidrug resistant tuberculosis patients in the Cape Province of South Africa

Little is known about the outcome of multidrug resistant (MDR) tuberculosis (TB) in developing countries. In this study, 443 patients with MDR-TB, defined as resistance to two or more antituberculosis drugs, were identified over the 2-year period 1987 and 1988 in the Cape Province of South Africa. The 5-year outcome of the 343 (77%) patients that could be traced by questionnaire was evaluated retrospectively during 1992 and 1993. Of these, 240 (70%) were resistant to both isoniazid (H) and rifampicin (R) with or without resistance to other first-line antituberculosis drugs and 103 (30%) were resistant to H or R and/or other antituberculosis drugs. Mortality was 116 (48%) and 28 (27%) in these groups respectively with a significantly greater risk of death in the first group. Only 114 (33%) of all the MDR-TB patients were cured after 5 years, 50 (15%) were respiratory disabled and 44 (13%) were still bacteriology positive. Twenty-four (7%) patients were lost during follow-up. Taking into account the high costs involved in treating MDR-TB patients and the scarce resources available in developing countries, more emphasis should be placed on direct observed therapy to cure newly diagnosed infectious drug sensitive tuberculosis patients, thus preventing MDR-TB rather than treating it.

Tuberculosis drug resistance in the Western Cape

OBJECTIVES

Drug resistance is a serious problem in the treatment of tuberculosis and a threat to successful tuberculosis control programmes. Local health workers have expressed concern that the increasing tuberculosis epidemic in the Western Cape is partly attributable to drug resistance. The aim of this study was to determine the prevalence of tuberculosis drug resistance (including multidrug resistance) and to investigate possible relationships between drug resistance and patient demographic characteristics.

DESIGN, SETTING, SUBJECTS, OUTCOME MEASURES

During a defined period, all adult (> or = 15 years) patients with pulmonary tuberculosis (confirmed by culture) from all tuberculosis clinics in the Western Cape were included. Previous tuberculosis treatment history was obtained by interviews, utilising a standardised questionnaire. Acquired drug resistance was determined on cultures from patients with a prior history of tuberculosis treatment, while initial resistance was determined from tuberculosis cases with no history of previous treatment.

RESULTS

Data from 7,266 patients were analysed. After adjusting for missing information by way of a random sample validation study, 32% of patients were found to have a history of previous treatment, 63% indicated no previous treatment, and in 5% the treatment history was unknown. Rates for initial resistance were found to be low at 3,9% for isoniazid, 1,1% for rifampicin and 0,2% for ethambutol. Combined resistance to isoniazid and rifampicin (multidrug resistance) was found to be 1,1% in patients not treated before. Acquired resistance rates were higher at 10,8% for isoniazid, 4,2% for rifampicin, 0,3% for ethambutol and 4,0% for multidrug resistance. Logistic regression analysis of the data indicated that drug resistance was not influenced by population group, gender or age. Patients with a history of tuberculosis treatment were found to be at an increased risk of developing drug resistance (relative risk 2,6). Some regions in the Western Cape had higher proportions of previously treated patients with consequent higher acquired resistance rates.

CONCLUSIONS

Results from this study indicated that drug resistance is currently not a major problem in the Western Cape, rates comparing favourably with those reported from developed countries and being much lower than those for developing countries. Every effort should therefore be made to maintain the status quo and to prevent the emergence of further resistance. The priority for tuberculosis control in the Western Cape should remain to limit transmission of the disease by reducing the infectious pool through improved cure of (especially) smear-positive cases.