Prevalence and phenotypic trajectories of hypoxaemia among hospitalised adults in Kenya: a single-centre, prospective cohort study

Abstract

Objective: Global medical oxygen security is limited by knowledge gaps in hypoxaemia burden and oxygen access in low-income and middle-income countries. We examined the prevalence and phenotypic trajectories of hypoxaemia among hospitalised adults in Kenya, with a focus on chronic hypoxaemia. Design: Single-centre, prospective cohort study. Setting: National tertiary referral hospital in Eldoret, Kenya between September 2019 and April 2022. Participants: Adults (age ≥18 years) admitted to general medicine wards. Primary and secondary outcome measures: Our primary outcome was proportion of patients who were hypoxaemic (oxygen saturation, SpO2 ≤88%) on admission. Secondary outcomes were proportion of patients with hypoxaemia on admission who had hypoxaemia resolution, hospital discharge, transfer, or death among those with unresolved hypoxaemia or chronic hypoxaemia. Patients remaining hypoxaemic for ≤3 days after admission were enrolled into an additional cohort to determine chronic hypoxaemia. Chronic hypoxaemia was defined as an SpO2 ≤ 88% at either 1-month post-discharge follow-up or, for patients who died prior to follow-up, a documented SpO2 ≤88% during a previous hospital discharge or outpatient visit within the last 6 months. Results: We screened 4104 patients (48.5% female, mean age 49.4±19.4 years), of whom 23.8% were hypoxaemic on admission. Hypoxaemic patients were significantly older and more predominantly female than normoxaemic patients. Among those hypoxaemic on admission, 33.9% had resolution of their hypoxaemia as inpatients, 55.6% had unresolved hypoxaemia (31.0% died before hospital discharge, 13.3% were alive on discharge and 11.4% were transferred) and 10.4% were lost to follow-up. The prevalence of chronic hypoxaemia was 2.1% in the total screened population, representing 8.8% of patients who were hypoxaemic on admission. Chronic hypoxaemia was determined at 1-month post-discharge among 59/86 patients and based on prior documentation among 27/86 patients. Conclusion: Hypoxaemia is highly prevalent among adults admitted to a general medicine ward at a national referral hospital in Kenya. Nearly 1 in 11 patients who are hypoxaemic on admission are chronically hypoxaemic.