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Abstract
Background This review aims to synthesise available evidence on the prevalence of chronic obstructive pulmonary disease (COPD), associated risk factors, hospitalisations and COPD readmissions in Africa.
Method Using the Met-Analyses and Systematic Reviews of Observational Studies guideline, electronic databases were searched from inception to 1 October 2021. The quality of studies was assessed using the Newcastle-Ottawa Scale. Evidence from retrieved articles was synthesised, and a random-effect model meta-analysis was conducted. The protocol was registered on PROSPERO.
Results Thirty-nine studies met the inclusion criteria, with 13 included in the meta-analysis. The prevalence of COPD varied between the Global Initiative for Chronic Obstructive Lung Disease (2%–24%), American Thoracic Society/European Respiratory Society (1%–17%) and Medical Research Council chronic bronchitis (2%–11%) criteria, respectively. Increasing age, wheezing and asthma were consistent risk factors for COPD from studies included in the narrative synthesis. Our meta-analysis indicated that prior tuberculosis ((OR 5.98, 95% CI 4.18 to 8.56), smoking (OR 2.80, 95% CI: 2.19 to 3.59) and use of biomass fuel (OR 1.52, 95% CI: 1.39 to 1.67)) were significant risk factors for COPD. Long-term oxygen therapy (HR 4.97, 95% CI (1.04 to 23.74)) and frequent hospitalisation (≥3 per year) (HR 11.48, 95% CI (1.31 to 100.79)) were risk factors associated with 30-day COPD readmission.
Conclusion This study not only highlights specific risk factors for COPD risk in Africa but also demonstrates the paucity and absence of research in several countries in a continent with substantial COPD-related mortality. Our findings contribute towards the development of evidence-based clinical guidelines for COPD in Africa.
PROSPERO registration number
CRD42020210581.
- long term oxygen therapy (LTOT)
- tuberculosis
- COPD exacerbations
- COPD epidemiology
Data availability statement
No data are available. ‘Not applicable’.
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WHAT IS ALREADY KNOWN ON THIS TOPIC
Chronic obstructive pulmonary disease (COPD) and COPD-related hospital admissions are prevalent in sub-Saharan Africa; yet the research on the risk factors for COPD and COPD hospital admission/readmission on the continent is sparse and diverse. There is a growing knowledge of the prevalence of, risk factors and predictors of COPD, COPD admission and readmission. Most of the published studies are from developed countries; hence, a systematic review is needed to identify predictors/risk factors of COPD, COPD admission and readmission in Africa.
WHAT THIS STUDY ADDS
This study provides a comprehensive and up-to-date summary of the prevalence and risk factors of COPD in Africa. It also highlights the predictors of COPD admission and readmission that are unique to the continent.
HOW THIS STUDY MIGHT AFFECT RESEARCH, PRACTICE OR POLICY
This study identified intervention opportunities that policymakers and healthcare professionals could target to reduce the burden of COPD in Africa.
Introduction
Chronic obstructive pulmonary disease (COPD) is characterised by airflow limitation in the lungs and is associated with an abnormal inflammatory reaction of the lung to tobacco smoke, noxious particles or gases.1 COPD was ranked the fourth (out of 369) condition with the highest disability-adjusted life years in the Global Burden of Disease report in 2019.2 The Global Burden of Disease 2019 study estimated 212.3 million prevalent cases of COPD reported worldwide3 with 3.3 million deaths.4 Furthermore, COPD is one of the top three leading causes of death worldwide,1 with 90% of COPD deaths occurring in low and middle-income countries (LMIC),4 mainly in South Asia and sub-Saharan Africa.5
Despite growing knowledge of the incidence and prevalence of COPD globally, there are scarce data from many countries in Africa.5 6 In spite of the increasing burden of COPD in Africa being recognised as the second highest in the WHO regions category,6 there are no published reviews that systematically highlight the predictors and risk factors for COPD in Africa.7 It is, therefore, vital to understand these factors as COPD in Africa has been described as an ‘incoming storm’8 and ‘the silent epidemic’.9
There are several factors prevalent in Africa associated with COPD. Tobacco smoking is a major risk factor for the development and progression of COPD10 with its use in Africa on the increase.11 There are 1.1 billion smokers in the world, of which 80% live in LMICs.12 There is also an increase in the ‘non-smoking’ COPD population in Africa, which highlights the multifactorial pathogenesis of COPD.13 Other factors associated with COPD, especially in Africa, are environmental air pollution, exposure to combustion products of biomass fuel, occupational dusts/vapours/fumes, previous pulmonary tuberculosis (TB), HIV infection, poor diet, malnutrition (including effects in utero), low socioeconomic status and childhood respiratory infections.14 15 Environmental pollution is a significant problem, with over 90% of households and individuals in rural Africa exposed to biomass fuel.16 17
COPD is one of the leading causes of emergency hospitalisation and readmission in the world.18 19 Exacerbation of COPD has been reported to be one of the main reasons for admission and readmission of patients to hospital in high-income countries, with severe negative impacts on the patient and the healthcare system.20 Prevention of exacerbation of COPD has been recognised as an international priority in improving the prognosis of COPD and reducing associated healthcare costs.19 21 Two recent systematic reviews on readmission for COPD focused on studies in developed countries with none from African countries to date,20 22 highlighting the need to gather and synthesise evidence from a continent with a high COPD burden to complement existing knowledge.
Although there has been a consensus on the importance of identifying risk factors for COPD and healthcare utilisation in Africa,15 23 there is no comprehensive review summarising these risk factors implicated in the development of, and hospitalisation for COPD in Africa. The available systematic reviews have focused on the prevalence, diagnosis and burden of COPD.6 24–27 The present systematic review aims to summarise identified predictors/risk factors of COPD and healthcare utilisation in Africa and review clinical characteristics and outcomes.
Methods
This study was reported following the Meta-Analyses and Systematic Reviews of Observational Studies Guidelines28 The protocol was registered on PROSPERO.
Data sources and search strategy
We searched four electronic databases (Medline, Scopus, Embase and Cumulative Index to the Nursing and Allied Literature (CINAHL) for relevant papers from the inception date to 1 October 2021. We used four main search keywords (‘COPD’, ‘risk factors/consequences’, ‘admission/readmission’ and ‘Africa’) as ‘concepts’ based on previous systematic reviews relevant to the topic.20 Alternative terms and synonyms for each of the key concepts were identified as free-text terms and used to search in the databases as title and abstract. Database-specific controlled vocabulary/subject headings were also used in the search (online supplemental table S1). Detailed information on the search strategy is found in online supplemental table S2. Relevant studies identified through the reference list of eligible papers were also included.
Supplemental material
Eligibility criteria
Studies were included based on the following inclusion criteria:
Studies included the numerical estimates of the prevalence of risk factors/predictors/causes for COPD or COPD admission or readmission; admission/readmission (s) of COPD clearly defined as one or more admission where COPD was the primary diagnosis for the admission/readmission (s)
Studies undertaken in any of the 54 African countries.
Studies were excluded based on these criteria:
Studies were conference abstracts, editorial reports and letters, theses or reviews.
Studies described the implementation of interventions or programmes beyond normal care.
Studies were published in any language other than English.
Studies undertaken in countries that are not in Africa.
Study definitions
COPD has been previously described based on both clinical and pathological presentations such as chronic bronchitis and emphysema.29 These definitions do not explain the physiological impairment of the lungs that is manifest by reduced expiratory volume linked to the vital capacity of the lungs. A clear definition of COPD based on spirometry measures (a postbronchodilator ratio of forced expiratory volume in one second (FEV1) to forced vital capacity (FVC) of less than 70% (FEV1/FVC<0.7)) has been provided by the Global Initiative for Chronic Obstructive Lung Disease (GOLD)1 and the American Thoracic Society/European Respiratory Society (ATS/ERS) guidelines30 (online supplemental table S3). It has been acknowledged that the presence of mucus hypersecretion seen in chronic bronchitis can occur without airflow limitation in some patients. Hence, chronic bronchitis or the occurrence of cough and sputum production for at least 3 months in two consecutive years in a person in whom other causes of chronic productive cough have been excluded has been used in studies.1 For the purpose of this review, COPD definition will be based on spirometry (1 and 2) and chronic bronchitis measurement will be termed the non-spirometry3 measure:
The GOLD criteria1.
TheATS/ERS criteria,30 (GOLD and ATS/ERS criteria both defined as a postbronchodilator ratio of FEV1 to FVC of less than 70% (FEV1/FVC<0.7)).
The British MRC definition of chronic bronchitis, defined as ‘chronic productive cough on most days for 3 months in 2 consecutive years in a person in whom other causes of chronic productive cough have been excluded’.1
Study selection and data extraction
Studies were exported into the Rayyan QCRI web app for systematic reviews following the removal of duplicates in EndNote X9 (Thomson Reuters, USA). Two authors (CMN and KO) independently screened titles and abstracts of potential studies. The full text of eligible articles following the initial screening was independently reviewed by two authors (CMN and KO) to ensure that included studies met the eligibility criteria. Disagreements on selected papers between independent reviewers were resolved by a third author (SB). Data were reviewed and extracted from eligible studies according to a standardised format based on variables of interest, such as study population, study design, age, gender, smoking status, the prevalence of COPD and readmission rates. The adjusted OR measurements of association were extracted from the included studies.
Risk-of-bias assessment
Two authors (CMN and KO) independently assessed the methodological quality of each included study using the Newcastle-Ottawa Scale31 for cohort studies and adapted form for cross-sectional studies.32 These tools are mainly employed for the appraisal of non-randomised studies. The scale evaluates the selection, comparability and outcome of the studies, using a ‘star’ system with a maximum of nine stars for each study.31 Two authors (CMN and KO) independently assessed the quality of the studies and discrepancies were resolved by consensus (CMN, KO and SB).
Data synthesis
The heterogeneity and inconsistencies in reporting risk factors across studies prevented the inclusion of all the results from the studies retrieved in the subsequent meta-analysis. The meta-analysis was conducted using summary data from 13 studies to synthesise adjusted ORs for risk factors where results were reported consistently. The pooled adjusted ORs and 95% CIs were estimated in a meta-analysis if at least five studies reported results that were sufficiently similar.33 Only studies that used the same reference category for the smoking variable were included in the meta-analysis. Similar analyses were performed for risk factors of COPD admission/readmission. The heterogeneity of included studies was addressed by applying the random-effects model in Stata V.16.0, using the I2 statistic to examine between-study heterogeneity. The heterogeneity was substantial if the value of I2 was >50% and having a p value of >0.1 was considered an indicator of lack of heterogeneity.
Results
The search identified 552 papers, of which 87 were duplicates and excluded. Following the initial screening of 465 titles and abstracts, 149 full-text articles were assessed for eligibility and 39 papers met the inclusion criteria. The detailed selection process is shown in figure 1. The result of the quality assessment showed that 38 studies (97.4%) had five or more stars with one study (2.6%) having three stars (online supplemental table S4).
Study flowchart of included studies. COPD, chronic obstructive pulmonary disease.
Study characteristics
Table 1 shows the summary of relevant characteristics from 39 studies, which included 100 722 participants. Thirty-four of the studies (87%) were cross-sectional studies, with two studies (5%) conducted prospectively and another three (8%) conducted retrospectively. The studies were conducted across 14 of the 54 countries (26%) in the African continent. Five (out of 18) East African countries contributed the largest number of studies (n=16),15 17 34–47 followed by four (out of 6) North African countries with eight studies,48–55 two (out of 16) West African countries contributing seven studies56–61 and one (out of 5) Southern African countries62–65 and two (out of 9) Middle African countries66–69 both contributing four studies each. Seven studies were conducted in Uganda15 36 41–45; six in Nigeria56–59 61 70; four in South Africa62–65; three each in Cameroon,67–69 Egypt,48 54 55 Morocco,51 52 54 Tanzania17 40 47 and Tunisia49 50 54; two each in Algeria,53 54 Ethiopia,34 46 Malawi,35 37 Rwanda38 39 and one each in Cape Verde60 and Democratic Republic of Congo.66 Thirty-five of the included studies (92%) were published within the last decade (2010–2020).
Characteristics of included studies
Prevalence of COPD, COPD admission and readmission
Fourteen studies described COPD prevalence based on GOLD spirometric criteria,17 36 37 39–41 46 48 50 52 59 62 64 67 10 on ATS/ERS spirometric criteria15 35 36 39 42 44 51 61 66 69 while 7 studies were on both GOLD and ATS/ERS criteria.45 47 49 51 55 57 69 Five studies utilised the MRC description of chronic bronchitis38 43 54 58 63 with one reporting both chronic bronchitis (MRC) and COPD (ATS/ERS) criteria.43 Thirty-one studies reported a total of 41 rates of COPD prevalence based on spirometry while five studies reported nine rates of chronic bronchitis prevalence based on MRC criteria (table 1). The prevalence of COPD ranged from 2% to 24% (GOLD criteria) and 1% to 17% (ATS/ERS criteria). The prevalence of chronic bronchitis ranged from 2% to 11% (MRC criteria).
Eight studies from North African countries (4 out of 8) reported on the prevalence of COPD based on GOLD spirometry criteria ranging from 4.1% to 12.6%, ATS/ERS criteria from 5.3% to 17.4% and non-spirometry chronic bronchitis criteria from 2.2% to 3.7%. Twenty-eight studies from the sub-Saharan African countries reported the prevalence of COPD via GOLD criteria from 1.6% to 23.8%, ATS/ERS criteria from 1.4% to 17.4% and chronic bronchitis MRC criteria from 2.2% to 10.7%.
Two studies reported the rate of COPD admission as 56% over 12 months65 and 8% over 5 years56 of study period, respectively. Three studies reported the rate of COPD readmission as 6%34 within 30 days postdischarge, 44% over 12 months65 and 46% over 10 years of study period.53
Risk factors for COPD, COPD admission and readmission
Twenty-one studies reported 12 possible risk factors for COPD.15 17 36–40 42 44–46 49 50 55 57 58 61 63 66 68 69 Of these, three factors (biomass fuel, TB, and smoking) were considered for pooled adjusted ORs as the remaining factors were examined in fewer than five studies.33 No study reported on risk factors for COPD admission.
Long-term oxygen therapy (HR 4.97, 95% CI 1.04 to 23.74) and frequent hospitalisation (≥3 in a year) (HR 11.48, 95% CI 1.31 to 100.79) were found to be risk factors associated with 30 days COPD readmission.34 Detailed summaries of the risk factors associated with COPD and COPD readmission are presented in online supplemental table S5 and S6.
Meta-analysis
Meta-analysis was not performed on all results because of the lack of data on admissions/readmissions and the heterogeneity of selected studies. We included 13 studies comprising 23 035 patients in the meta-analysis for the examination of COPD risk factors. Seven of the studies with 18 314 patients reported smoking as a risk factor, seven studies comprising 18 600 patients reported the use of biomass as fuel as a risk factor while five studies with 17 114 patients reported history of TB as a risk factor. The pooled adjusted OR indicates that previous pulmonary TB (OR 5.98, 95% CI 4.18 to 8.56), smoking (OR 2.80, 95% CI 2.19 to 3.59) and use of biomass as fuel (OR 1.52, 95% CI 1.39 to 1.67) are significant risk factors for COPD in Africa. These are presented using forest plots (figure 2A–C). The heterogeneity between studies was not significant with I2 values of 0% (95% CI 0%, 61%, p=0.84), 15% (95% CI 0%, 61%, p=0.31) and 37% (95% CI 0%, 70%, p=0.12) for TB, smoking status and biomass as fuel, respectively (figure 2A–C).
(A–C) The results of pooled adjusted ORs for tuberculosis, smoking status and biomass as fuel respectively. COPD, chronic obstructive pulmonary disease; REML, restricted maximum likelihood.
Narrative synthesis for risk factors for COPD
Older age
Thirteen out of 19 studies that examined the relationship between age and COPD, associated older age across various age ranges (≥30 years to≥74 years) with increased risk of COPD. Meghji et al reported that the odds of having COPD within the age range of 50–59 years compared with ≥60 varied significantly from OR of 4.66 to 10.12.37 This was confirmed in research by Magitta et al where the risk of COPD significantly increased in patients aged between 51 and 60 (OR 9.66, 95% CI 4.79 to 18.25) compared with those between 41 and 50 (OR 4.02, 95% CI 1.10 to 14.66) in relation to those aged between 30 and 40.17 Desalu et al also reported a significant association between older age (65–74 and ≥74) and COPD compared with those <35 years. However, ages between 55 and 64 had a significant protective effect with an OR of 0.20 in comparison to <35.58
Other risk factors
Three studies reported patients with a wheeze to be more likely to develop COPD45 55 69 while no association was found in patients with chronic cough and sputum production.15 45 55 69 For example, Pefura-Yone et al found patients with lifetime wheeze to have almost threefold increased odds of developing COPD compared with those without lifetime wheeze.69 Asthma was associated with increased risk for COPD in two studies50 61 while no association was found with other comorbidities (such as hypertension, heart failure, pneumonia and diabetes) and COPD. Several studies investigated sex (n=13), ethnicity (n=2), Body Mass Index (n=8), HIV (n=6), living in urban areas (n=3), educational level (n=14) and occupational exposure to dusts, gases or fumes (n=6) as risk factor for COPD, but the results were inconsistent. One study found men to have a 3.0 odds of COPD compared with being 39women; however, another 10 studies found no association between sex and COPD.
Discussion
This is the first systematic review to examine and summarise the risk factors for COPD and COPD admission in Africa. Our meta-analysis showed that history of TB, smoking and use of biomass fuel are associated with an increased risk of COPD. Increasing age, wheezing and comorbid asthma are also risk factors for COPD. We found that the prevalence of COPD ranged from 1% to 24% depending on the assessment criteria and setting. We estimated, for the first time, the prevalence of COPD in Africa and we also identified COPD risk factors that are of importance on the continent. Nevertheless, these estimates were from only 14 out of the 54 countries. This highlights the urgency and need for more research work to be conducted in COPD across Africa, considering that 90% of the COPD-related mortality rate occurs in Africa.
Our study reports the prevalence of COPD ranging from 1% to 24% is consistent with previous reviews that reported COPD prevalence in sub-Saharan African countries between 4% and 25%.24 25 Another review reported COPD prevalence in Africa in all spirometry-confirmed cases to be 13.4% and non-spirometry-confirmed cases to be 4.0%.24 This was different to our result on spirometric confirmed cases and non-spirometric confirmed cases. The wide variation in the prevalence of COPD in Africa may be due to variations in the study population and setting, age of participants and criteria used for diagnosis.14 This is similar to the result of a recent systematic review that focused on developed countries.20
The 12-month and 5-year admission rates for COPD were 56% and 8%, respectively, which are inconsistent with other studies in the literature. The rate of readmission ranged from 6% to 46%, depending on the follow-up period. Other reviews have only considered readmission from COPD in developed countries.20 22 The COPD readmission rate reported in African populations is lower for 30 days of readmission (6.0%) compared with developed countries that varied from 8.8% to 26.0%;22 however, there was consistency in 1-year readmission. It is vital to highlight the lack of studies on readmissions in Africa and the challenges accessing affordable hospital care for those in need. Three studies reported COPD readmission (1=30 day, 1=1 year and 1=10 years). On the contrary, 32 studies in developed countries reported 30 days, 90 days and 1-year all-cause COPD readmission22 and 54 studies reported 30 days, 90 days and 1-year COPD-related readmission.20
Reasons for the differences in the figures observed between Africa and developed countries may include the economic burden of COPD due to poor access and affordability to hospital healthcare for many populations from low socioeconomic areas. Another plausible reason could reflect the widespread under-recognition and underdiagnosis of COPD.1 There is also diversity both within and between African countries (eg, Northern African countries vs sub-Saharan African countries). Our study clearly highlights the importance of further research in this area with only 14 countries (out of 54) contributing to the studies.
Consistent with the literature, our results found previous TB infection to be independently associated with COPD.71 TB can result in airflow obstruction meeting the spirometric criteria for COPD. TB is known to trigger airway inflammatory response that consequently results in a decrease in lung volume.71 There is the inflammatory response of TB known by its increased oxidative stress in the airways and lung parenchyma which are vital pathological processes in the development and progression of COPD.71 The high prevalence of TB worldwide especially in many developing countries denotes a considerable public health significance both to epidemiologists and healthcare providers.
Asthma was found to be strongly associated with the development of COPD. Poorly controlled asthma, for example, in the absence of access to affordable therapy, can result in airflow obstruction that meets the spirometric criteria for COPD. This is in line with a report from the Tucson study that found patients with asthma to have a 12-fold higher risk of developing COPD compared with those without asthma.72 Although the reversibility of pulmonary obstruction in response to treatment is a hallmark of asthma, it has been shown to decrease over time in some asthmatic patients, to the point of irreversible or only partially reversible airway obstruction.73 Systematic reviews have found an increased frequency of COPD exacerbation and hospitalisation in patients with asthma.74 75 This increases the disease burden for patients with COPD. Clinical respiratory guidelines that are tailored to the needs and demands of African countries by the global community may improve the diagnosis and management of COPD but are often lacking.76 Accessibility, availability and affordability of COPD and respiratory medicines will go a long way in the management of COPD.
The use of biomass fuel for cooking and heating was found to be a significant risk factor for COPD. Globally almost three million people use biomass and coal as their essential source of energy for cooking, heating and other household requirements.77 Over 90% of households in rural Africa are exposed to biomass fuel with women and young children, particularly at increased risk of exposure during food preparation.17 Exposure to solid fuels for cooking is associated with premature 3.8 million deaths a year.78 Twenty-five per cent of deaths from COPD in adults in LMICs are due to exposure to household air pollution.78 Cooking in poor ventilated kitchens was associated with a fourfold increase in development of COPD.46 In poorly ventilated dwellings, indoor smoke can be 100 times higher than appropriate levels for fine particles.78 There is also the impact of pollution from industrialisation comprising of fossil fuel-driven machineries with limited implementation of safety and health standards in many settings. This highlights the potential for effective policies and strategies to reduce the exposure and impact of biomass fuels and the COPD burden of disease.
Seven studies found strong associations between smoking and COPD. Smoking is recognised to be the most important cause of COPD in high-income settings. This relationship was substantial in subgroups of current smokers, former smokers and combining current and former smokers. Forey et al in a meta-analysis comprising of 218 studies demonstrated a clear relationship between smoking (for ever, current and former smoking) and COPD.79 Many of the African countries have lower tobacco taxation rates, weaker smoke-free policies with less stringent tobacco advertising restrictions in comparison to higher income and developed countries. Hence, they are less likely to implement programmes aimed at prohibiting smoking in public places.11 Urgent action is required by all stakeholders, including governments in implementing and advocating prohibition of smoking in public places.
The results of individual studies have demonstrated that the odds of having COPD are greater in older age groups compared with younger age groups. This finding is unsurprising and consistent with previous reports.20 22 The average life expectancy in African countries has increased since 2000 from 50.8 years to 61.2 years in 2016.80 This increase suggests that the burden of COPD will also be increasing and, therefore, requires urgent attention. The higher COPD risk among individuals in the older age category may be an indication of cumulative exposures during lifetime or ageing of the airways and parenchyma associated with structural changes in COPD.1 Interestingly, the age range included in some studies was as low as 30 years suggesting early onset, with early and continuous exposure to biomass and noxious fumes. These in combination with poor lung growth and development associated with poverty and inadequately treated respiratory infections increased the burden of COPD disease. African governments need to implement urgent policies to reduce airborne exposures, tobacco smoke and indoor and outdoor pollution.
Two papers reported risk factors for readmission of COPD34 65 with one reporting only p values for the multivariate analysis. Anbesse et al found long-term use of oxygen therapy (a marker of respiratory failure, but a treatment not widely available in Africa) and frequent hospitalisation (≥3) in a year to be associated with an increased risk of COPD readmission.34 This is consistent with a recent systematic review undertaken in developed countries.20 Patients on long-term oxygen therapy are likely to have severe and advanced disease thereby increasing their risk of readmission. Similarly, frequent hospitalisation may indicate suboptimal management or disease severity.
There are limitations to this study. We limited our literature search to studies published in English; hence, it is possible that we might have missed studies published in other languages. In addition, Africa is geographically large and diverse with varying health determinants and socioeconomic factors. Diversity extends to differences within countries such that context varies greatly. The covariates reported in the studies included in the meta-analysis were not uniform, and the OR derived from various studies was adjusted for different covariates. There is also the variation in the method of diagnosing COPD, which reflects the diversity of formal and informal healthcare system found in most African countries. The diverse healthcare system is intertwined with social, cultural, and economic/affordability issues which are strong barriers to early assessing of appropriate healthcare services. Appropriate management of COPD will require appropriate diagnosis involving access to spirometry. A majority of healthcare facilities in Africa lack spirometry and must rely solely on clinical features for diagnosis, perhaps supported by case finding tools.81 There is also the issue of affordability of the life-long treatments for appropriate management of COPD. Adherence will continue to be severely affected by affordability of health cost imposed on poor income households. The availability of COPD therapy at an affordable price will be a starting point in the prevention and management of COPD, as will the effective implementation of guidelines.82 Further studies in partnership with international communities are urgently needed to tackle this global public health issue. We recognise that the causes of poorly reversible airflow obstruction in LMIC settings are diverse and that not everyone meeting spirometric criteria for COPD has an exposure-driven airway disease. In addition, respiratory exposures in LMIC may cause manifestations such as emphysema that are not necessarily associated with poorly reversible airflow obstruction despite being part of the COPD definition. These limitations are rarely adequately addressed in the individual studies we have summarised and are important areas for future research.
Conclusion
The prevalence of COPD is higher based on GOLD criteria (2%–24%) compared with ATS/ERS criteria (1%–17%) and MRC chronic bronchitis criteria (2%–11%). Comorbidity (TB and asthma), smoking and use of biomass as fuel are significant risk factors for COPD in Africa. Long-term use of oxygen therapy and frequent hospitalisation (≥3) in a year are associated with increased risk of COPD readmission. Further studies are needed for clearer reporting of the magnitude of the problem. These identified factors potentially guide the development of evidence-based guidance and culturally acceptable local interventions tailored to the demands and needs of various regions on the African continent.
Data availability statement
No data are available. ‘Not applicable’.
Ethics statements
Patient consent for publication
Ethics approval
Not applicable.
References
Supplementary materials
Supplementary Data
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Footnotes
Twitter @chidi_sr
SB and KO contributed equally.
Contributors CMN, SB, and KO conceived and drafted the review. All authors have critically appraised and approved the final version for submission. CMN is the guarantor.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
Supplemental material This content has been supplied by the author(s). It has not been vetted by BMJ Publishing Group Limited (BMJ) and may not have been peer-reviewed. Any opinions or recommendations discussed are solely those of the author(s) and are not endorsed by BMJ. BMJ disclaims all liability and responsibility arising from any reliance placed on the content. Where the content includes any translated material, BMJ does not warrant the accuracy and reliability of the translations (including but not limited to local regulations, clinical guidelines, terminology, drug names and drug dosages), and is not responsible for any error and/or omissions arising from translation and adaptation or otherwise.