Multimorbidity and associations with clinical outcomes in a middle-aged population in Iran: a longitudinal cohort study
Date
2022-04-19
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Abstract
Background As the populations of lower-income
and middle-income countries age, multimorbidity is
increasing, but there is little information on its longterm consequences. We aimed to show associations
between multimorbidity and outcomes of mortality
and hospitalisation in Iran, a middle-income country
undergoing rapid economic transition.
Methods We conducted a secondary analysis of
longitudinal data collected in the Golestan Cohort
Study. Data on demographics, morbidities and lifestyle
factors were collected at baseline, and information
on hospitalisations or deaths was captured annually.
Logistic regression was used to analyse the association
between baseline multimorbidity and 10-year mortality,
Cox-proportional hazard models to measure lifetime risk
of mortality and zero-inflation models to investigate the
association between hospitalisation and multimorbidity.
Multimorbidity was classified as ≥2 conditions or number
of conditions. Demographic, lifestyle and socioeconomic
variables were included as covariables.
Results The study recruited 50 045 participants aged
40–75 years between 2004 and 2008, 47 883 were
available for analysis, 416 (57.3%) were female and 12
736 (27.94%) were multimorbid. The odds of dying at 10
years for multimorbidity defined as ≥2 conditions was
1.99 (95% CI 1.86 to 2.12, p<0.001), and it increased with
increasing number of conditions (OR of 3.57; 95% CI 3.12
to 4.08, p<0.001 for ≥4 conditions). The survival analysis
showed the hazard of death for those with ≥4 conditions
was 3.06 (95% CI 2.74 to 3.43, p<0.001). The number of
hospital admissions increased with number of conditions
(OR of not being hospitalised of 0.36; 95% CI 0.31 to 0.52,
p<0.001, for ≥4 conditions).
Conclusion The long-terms effects of multimorbidity on
mortality and hospitalisation are similar in this population
to those seen in high-income countries.