Time trends in maternal hypertensive disorder incidence in Brazil, Russian Federation, India, China, and South Africa (BRICS): an age-period-cohort analysis for the GBD 2021

Abstract

Objectives: Maternal hypertensive disorder (MHD) is a leading cause of significant maternal and fetal mortality and morbidity. The BRICS nations are crucial in the global MHD landscape, given their large populations and varied healthcare infrastructures. This investigation evaluates the incidence trends of MHD in BRICS countries from 1992 to 2021.

Study design and methods: Data on the number, all-age rate, age-standardized rate (ASR), and the relative change of MHD incidence from this study were sourced from the Global Burden of Disease (GBD) 2021 public dataset to investigate temporal trends in MHD incidence over three decades globally and in BRICS countries. The age-period-cohort (APC) model was used to estimate net drift, local drift, age-specific curves, and period (cohort) relative risks.

Results: A 15.87% increase in global MHD cases, alongside a 13.40% decrease in age-standardized incidence rates from 1992 to 2021. MHD incidence rates are declining across various BRICS age groups, except in China and Russian Federation, where most groups exhibit increasing trends. Annual net drift in MHD incidence ranges from - 4.25% in India to 2.38% in China. A shift in the age distribution of MHD cases from younger to older within the childbearing age range is observed in all BRICS nations. Countries exhibit similar age-effect patterns, with decreasing risk with increasing age, and varying period and cohort effects, indicative of differential control measures and temporal incidence trends.

Conclusions: Global and BRICS-specific reductions in MHD incidence vary in magnitude. Customized preventive strategies, leveraging existing resources, are advisable for BRICS nations to address pregnancy complications. Enhancing primary healthcare and maternal care quality, particularly for older mothers, is imperative.

Keywords: Age-period-cohort model; BRICS; Incidence; Maternal hypertensive disorder.

Fig. 1

Local drifts of incidence rate and age distribution of incidences in global and BRICS, 1992–2021. (A) Local drifts of maternal hypertensive disorder incidence rate (estimates from age-period-cohort models) for 8 age groups (15–19 to 50–94 years), 1992–2021. The dots and shaded areas indicate the annual percentage change of incidence rate (% per year) and the corresponding 95% CIs. (B) Temporal change in the relative proportion of maternal hypertensive disorder incidences across age groups, 1992–2021.

Fig. 2

Age, period and cohort effects on maternal hypertensive disorder incidence in global and BRICS. (A) Age effects are shown by the fitted longitudinal age curves of incidence rate (per 100,000 person-years) adjusted for period deviations. (B) Period effects are shown by the relative risk of incidence rate (incidence rate ratio) and computed as the ratio of age-specific rates from 1992–1996 to 2017–2021, with the referent cohort set at 2002–2006. (C) Cohort effects are shown by the relative risk of incidence rate and computed as the ratio of age-specific rates from the 1940 cohort to the 2004 cohort, with the referent cohort set at 1972. The dots and shaded areas denote incidence rates or rate ratios and their corresponding 95% CIs