Premature mortality in children aged 6-9 years with neurological impairments in rural Kenya: a cohort study

Abstract

Background: Neurological impairments might significantly contribute to reduced life expectancy in low-income and middle-income countries (LMICs). There are no empirical studies of premature mortality in children with neurological impairments in Africa. This study estimated the risk of premature mortality in children with neurological impairments and identified risk factors and causes of death.

Methods: We did a cohort study based on a two-stage epidemiological survey in the Kilifi Health and Demographic Surveillance System (Kilifi, Kenya). Study participants were children aged 6-9 years. In the first stage, five trained field workers administered a low-cost screening tool to a random sample of households. In the second stage, we assessed for neurological impairments in five domains (epilepsy, cognitive impairments, vision impairments, hearing impairments, and motor impairments) using comprehensive clinical evaluation and extensive neuropsychological assessments. From the two-stage survey we identified a cohort of children with neurological impairment and a cohort of matched controls. We also enrolled an age-matched sample from the general population. The primary outcome was all-cause mortality. Mortality rates, standardised mortality ratio (SMR), and hazard ratios (HR) for risk factors were estimated and causes of death identified.

Findings: We enrolled 306 children with neurological impairment, 9912 survey controls, and 22 873 age-matched participants from the general population, and followed up the cohorts between June 1, 2001, and Aug 31, 2018. Median follow-up was 14·5 years (IQR 8·6-17·2). 11 (3·9%) of 284 children with neurological impairment, 92 (1·0%) of 9009 controls, and 272 (1·2%) of 22 873 participants in the general population sample died during the follow-up. Overall mortality rates were 309·8 per 100 000 person-years of observation (95% CI 126·7-492·9) in children with neurological impairment, 80·8 per 100 000 person-years of observation (64·3-97·3) in controls, and 98·8 per 100 000 person-years of observation (87·1-110·6) in the general population sample (mortality rate ratio 3·83, 95% CI 2·05-7·16, p<0·001, compared with controls; 3·13, 1·71-5·72, p<0·001, compared with the general population). Mortality risk in children with neurological impairment was not dependent on the severity of impairment (p=0·291) nor on a specific neurological impairment domain (p=0·205). The overall risk of death adjusted for age and sex was higher in children with neurological impairment compared with controls (HR 4·24, 95% CI 2·26-7·94, p=0·002). An SMR of 3·15 (95% CI 1·66-5·49) was obtained after using the general population sample as the reference for indirect standardisation. In multivariable risk factor analysis, developmental delay (adjusted HR 18·92, 95% CI 2·23-160·44, p=0·007) and severe malnutrition (20·92, 3·14-139·11, p=0·002) increased the risk of mortality in children with neurological impairment. Infections such as HIV/AIDS and accidents were common among all decedents.

Interpretation: The risk of premature mortality was higher in children diagnosed with neurological impairments compared with the general population and was increased by developmental delay and severe malnutrition. Child development and nutritional status should be assessed in all children in LMICs and tailored interventions started to improve outcomes.

Funding: Wellcome Trust, DELTAS Africa Initiative.

Figure 1

Flow diagram showing recruitment and follow-up of individuals with neurological impairments and controls

Figure 2

Estimated survival probability comparing individuals with neurological impairment versus controls