Adult and child malaria mortality in India: a nationally representative mortality survey

Abstract

Background: National malaria death rates are difficult to assess because reliably diagnosed malaria is likely to be cured, and deaths in the community from undiagnosed malaria could be misattributed in retrospective enquiries to other febrile causes of death, or vice-versa. We aimed to estimate plausible ranges of malaria mortality in India, the most populous country where the disease remains common.

Methods: Full-time non-medical field workers interviewed families or other respondents about each of 122,000 deaths during 2001-03 in 6671 randomly selected areas of India, obtaining a half-page narrative plus answers to specific questions about the severity and course of any fevers. Each field report was sent to two of 130 trained physicians, who independently coded underlying causes, with discrepancies resolved either via anonymous reconciliation or adjudication.

Findings: Of all coded deaths at ages 1 month to 70 years, 2681 (3·6%) of 75,342 were attributed to malaria. Of these, 2419 (90%) were in rural areas and 2311 (86%) were not in any health-care facility. Death rates attributed to malaria correlated geographically with local malaria transmission ratesderived independently from the Indian malaria control programme. The adjudicated results show 205,000 malaria deaths per year in India before age 70 years (55,000 in early childhood, 30,000 at ages 5-14 years, 120,000 at ages 15-69 years); 1·8% cumulative probability of death from malaria before age 70 years. Plausible lower and upper bounds (on the basis of only the initial coding) were 125,000-277,000. Malaria accounted for a substantial minority of about 1·3 million unattended rural fever deaths attributed to infectious diseases in people younger than 70 years.

Interpretation: Despite uncertainty as to which unattended febrile deaths are from malaria, even the lower bound greatly exceeds the WHO estimate of only 15,000 malaria deaths per year in India (5000 early childhood, 10 000 thereafter). This low estimate should be reconsidered, as should the low WHO estimate of adult malaria deaths worldwide.

Funding: US National Institutes of Health, Canadian Institute of Health Research, Li Ka Shing Knowledge Institute.

Figure 1. India, 2005: malaria mortality before age 70, by state

Numbers of deaths (thousands, ages 0-69 years) and age-standardised rates (with 99% confidence intervals). Rates are standardised in 5-year age groups to total Indian population. The high-malaria states include 12% of national deaths from all causes and 47% of all-India malaria-attributed deaths before age 70. Apart from these, the only states in which at least 50 malaria deaths at ages 0-69 were recorded in our study (with all-India malaria deaths in thousands) include: Madhya Pradesh (20), Gujarat (12), Andhra Pradesh (10), Bihar (13), Rajasthan (12), Uttar Pradesh (19), Maharasthra (9) and other states (11).

Figure 2. Geographic distributions of malaria-attributed mortality and slide P. falciparum rate

(a) Percentage of 2001-2003 mortality attributed to malaria in this study at ages 1 month to 69 years. Mortality is plotted as the smoothed results from the 5335 study areas with some malaria-attributed mortality, mapped to the locations of their PIN code addresses. (b) District-level 1995-2005 slide falciparum rate from the National Vector-borne Disease Control Programme statistics., High-malaria states comprise Orissa (OR), Jharkhand (JH), Chhattisgarh (CG) and Assam and all the smaller northeastern states except Sikkim (NE).

Figure 3. Age-specific all-India malaria-attributed death rates estimated from the present study, and those estimated indirectly for WHO

Within each age range, the all-India death rates from the present study are standardised in 5-year age groups to the 2005 Indian population. The vertical bars represent the upper and lower bounds (see text and supplementary appendix) based on physician coding. The numbers shown beside the main line represent the number of study deaths finally adjudicated to malaria for each age range.

Figure 4. Reported cases (in 2006) of meningitis, typhoid and dengue infections and estimated malaria infections (in 1995-2005), per 10,000 population, by state

Total cases reported to the Government of India program of meningitis, typhoid and dengue are divided by total population for 2005 for that state and malaria cases are divided by total slides tested for malaria. Similar results are seen if reported deaths are plotted for each disease. Note that the scales differ for each disease.