Changes in child mortality over time across the wealth gradient in less-developed countries

Abstract

Background: It is unknown whether inequalities in under-5 mortality by wealth in low- and middle-income countries (LMICs) are growing or declining.

Methods: All Demographic and Health Surveys conducted between 2002 and 2012 were used to measure under-5 mortality trends in 3 wealth tertiles. Two approaches were used to estimate changes in under-5 mortality: within-survey changes from all 54 countries, and between-survey changes for 29 countries with repeated survey waves. The principal outcome measures include annual decline in mortality, and the ratio of mortality between the poorest and least-poor wealth tertiles.

Results: Mortality information in 85 surveys from 929 224 households and 1 267 167 women living in 54 countries was used. In the subset of 29 countries with repeat surveys, mortality declined annually by 4.36, 3.36, and 2.06 deaths per 1000 live births among the poorest, middle, and least-poor tertiles, respectively (P = .031 for difference). The mortality ratio declined from 1.68 to 1.48 during the study period (P = .006 for trend). In the complete set of 85 surveys, the mortality ratio declined in 64 surveys (from 2.11 to 1.55), and increased in 21 surveys (from 1.58 to 1.88). Multivariate analyses suggest that convergence was associated with good governance (P ≤ .03 for 4 governance indicators: government effectiveness, rule of law, regulatory quality, and control of corruption).

Conclusions: Overall, under-5 mortality in low- and middle-income countries has decreased faster among the poorest compared with the least poor between 1995 and 2012, but progress in some countries has lagged, especially with poor governance.

Keywords: child mortality; global health; health disparities; wealth inequalities.

FIGURE 1

Under-5 mortality (5q0) among the poorest, middle, and least-poor tertiles estimated annually up to 10 years before the year of the survey (starting in 1995) in 85 surveys. The scatter represents the annual estimates in each year in each tertile (poorest is the left-most column of dots). Smoothed median spline curves fit to each wealth tertile’s data show the convergence in mortality. Under-5 mortality in the highest mortality groups, mostly the poorest, approached 400 per 1000 live births in the 1990s and declined precipitously.

FIGURE 2

Average annual decline of under-5 mortality (5q0) by wealth tertile in 29 countries with repeated DHS surveys (and 95% CI bars). Only the first and most recent surveys of countries with repeat surveys were used in this analysis. The absolute annual declines in 5q0 were greatest in the poorest tertile and smallest in the least poor.

FIGURE 3

Heterogeneity in convergence. The ratio between the poorest and least poor in the earliest (Initial) and most recent (Final) year of measurement within each survey shows that the mortality ratio has been diverging in 21 of the 85 surveys. Three-letter country codes identify the countries with divergence of mortality across the wealth gradient, measured as increasing mortality rate ratios over time (ARM, Armenia; AZE, Azerbaijan; BDI, Burundi; BFA, Burkina Faso; COD, Democratic Republic of the Congo; COG, Congo; ETH, Ethiopia; GUY, Guyana; HND, Honduras; HTI, Haiti; KHM, Cambodia; LSO, Lesotho; MLI, Mali; MWI, Malawi; NGA, Nigeria; PHL, Philippines; RWA, Rwanda; TLS, Timor; UKR, Ukraine).