The Impact of Poor Air Quality on Hospitalisation of Multi-morbid Patients: A Systematic Review

Background Exposure to poor air quality worsen existing health conditions, particularly amongst vulnerable patients, leading to increased healthcare utilization. We conducted a systematic review to explore the impact of exposure to poor quality on healthcare requirements in multi-morbid patients. Methods We searched six major databases (Medline via Ovid, Embase via Ovid, Web of Science, CINAHL, Global Health, and Scopus) using search terms grouped into sets relating to ‘air pollution,’ ‘multimorbidity,’ “association” and ‘hospitalisation.’ We were interested in the impact of common air pollutants (PM2.5, PM10, SO2, NO2, O3, and CO) and articles were screened independently by two researchers. The review was registered with The International Prospective Register of Systematic Reviews (CRD42022369757) and followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Results A total of nineteen studies were included. All six air pollutants increased hospitalisation amongst multi-morbid patients, especially those with diabetes and cardiovascular comorbidity. Females and the elderly (>65 years old) were the most vulnerable to the effects of air pollution, with an increase in hospitalisations of 9.23% and 6.35% when exposed to PM2.5 and PM10, respectively. Patients >65 years had a higher likelihood of hospitalisation for ischemic and haemorrhagic stroke when exposed to PM2.5 or PM10 at warm season. Patients (≥70 years) who had cardiovascular and pulmonary comorbidity were 3.9% more likely to be hospitalised for a cardiopulmonary event with a rise in NO2 levels. We found an intersectional effect (referred to as “the CADC effect” - Climatic changes, Air pollutant, Demographics, Chronic conditions) that influenced the likelihood of hospitalisation. Conclusions Future research is required to further understand this CADC effect in other high-risk population. Key messages • Females, elderly, those with cardiovascular, and pulmonary comorbidity are at the highest risk of hospitalisation with poor air quality. • The CADC effect explains the intersectional effect between hospitalisation in multimorbid patients, patients demographics and chronic conditions, and air pollution and temperature effects.