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

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.

Factors associated with isolated right heart failure in women: a pilot study from western Kenya.

BACKGROUND: Small observational studies have found that isolated right heart failure (IRHF) is prevalent among women of sub-Saharan Africa. Further, several risk factors for the development of IRHF have been identified. However, no similar studies have been conducted in Kenya. OBJECTIVE: We hypothesized that specific environmental exposures and comorbidities were associated with IRHF in women of western Kenya. METHODS: We conducted a case-control study at a referral hospital in western Kenya. Cases were defined as women at least 35 years old with IRHF. Control subjects were similarly aged volunteers without IRHF. Exclusion criteria in both groups included history of tobacco use, tuberculosis, or thromboembolic disease. Participants underwent echocardiography, spirometry, 6-min walk test, rest/exercise oximetry, respiratory health interviews, and human immunodeficiency virus (HIV) testing. Home visits were performed to evaluate kitchen ventilation, fuel use, and cook smoke exposure time, all surrogate measures of indoor air pollution (IAP). A total of 31 cases and 65 control subjects were enrolled. Surrogate measures of indoor air pollution were not associated with IRHF. However, lower forced expiratory volume at 1 s percent predicted (adjusted odds ratio [AOR]: 2.02, 95% confidence interval [CI]: 1.27 to 3.20; p = 0.004), HIV positivity (AOR: 40.4, 95% CI: 3.7 to 441; p < 0.01), and self-report of exposure to occupational dust (AOR: 3.9, 95% CI: 1.14 to 14.2; p = 0.04) were associated with IRHF. In an analysis of subgroups of participants with and without these factors, lower kitchen ventilation was significantly associated with IRHF among participants without airflow limitation (AOR: 2.63 per 0.10 unit lower ventilation, 95% CI: 1.06 to 6.49; p = 0.04), without HIV (AOR: 2.55, 95% CI: 1.21 to 5.37; p = 0.02), and without occupational dust exposure (AOR: 2.37, 95% CI: 1.01 to 5.56; p = 0.05). CONCLUSIONS: In this pilot study among women of western Kenya, lower kitchen ventilation, airflow limitation, HIV, and occupational dust exposure were associated with IRHF, overall or in participant subgroups. Direct or indirect causality requires further study.

OBSTRUCTIVE LUNG DISEASE AND EXPOSURE TO BURNING BIOMASS FUEL IN THE INDOOR ENVIRONMENT.

It is estimated that up to half of the world's population burns biomass fuel (wood, crop residues, animal dung and coal) for indoor uses such as cooking, lighting and heating. As a result, a large proportion of women and children are exposed to high levels of household air pollution (HAP). The short and long term effects of these exposures on the respiratory health of this population are not clearly understood. On May 9-11, 2011 NIH held an international workshop on the "Health Burden of Indoor Air Pollution on Women and Children," in Arlington, VA. To gather information on the knowledge base on this topic and identify research gaps, ahead of the meeting we conducted a literature search using PubMed to identify publications that related to HAP, asthma, and chronic obstructive pulmonary disease (COPD). Abstracts were all analyzed and we report on those considered by the respiratory sub study group at the meeting to be most relevant to the field. Many of the studies published are symptom-based studies (as opposed to objective measures of lung function or clinical examination etc.) and measurement of HAP was not done. Many found some association between indoor exposures to biomass smoke as assessed by stove type (e.g., open fire vs. liquid propane gas) and respiratory symptoms such as wheeze and cough. Among the studies that examined objective measures (e.g. spirometry) as a health outcome, the data supporting an association between biomass smoke exposure and COPD in adult women are fairly robust, but the findings for asthma are mixed. If an association was observed between the exposures and lung function, most data seemed to demonstrate mild to moderate reductions in lung function, the pathophysiological mechanisms of which need to be investigated. In the end, the group identified a series of scientific gaps and opportunities for research that need to be addressed to better understand the respiratory effects of exposure to indoor burning of the different forms of biomass fuels.

Waiting to inhale: An exploratory review of conditions that may predispose to pulmonary hypertension and right heart failure in persons exposed to household air pollution in low- and middle-income countries.

The health effects of exposure to household air pollution are gaining international attention. While the bulk of the known mortality estimates due to these exposures are derived from respiratory conditions, there is growing evidence of adverse cardiovascular health effects. Pulmonary hypertension and right heart failure are common conditions in low- and middle-income countries whose etiology may be related to common exposures in these regions such as schistosomiasis, human immunodeficiency virus, tuberculosis infections and other causes. While little is known of the interplay between exposure to household air pollution, right heart function and such conditions, the large burden of pulmonary hypertension and right heart failure in regions where there is significant exposure to household air pollution raises the possibility of a linkage. This review is presented in three parts. First, we explore what is known about pulmonary hypertension and right heart failure in low- and middle-income countries by focusing on eight common causes thereof. We then review what is known of the impact of household air pollution on pulmonary hypertension and posit that when individuals with one of these eight common comorbidities are exposed to household air pollution they may be predisposed to develop pulmonary hypertension or right heart failure. Lastly, we posit that there may be a direct link between exposure to household air pollution and right heart failure independent of pre-existing conditions which merits further investigation. Our overall aim is to highlight the multifactorial nature of these complex relationships and offer avenues for research in this expanding field of study.