The burden of COPD in Africa: a literature review and prospective survey of the availability of spirometry for COPD diagnosis in Africa

Authors


Corresponding Author A. Mehrotra, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK. Tel.: +44 151 7053169; Fax: +44 151 7053370; E-mail: anushka.mehrotra@ncl.ac.uk

Summary

Objectives  To ascertain the known burden of chronic obstructive pulmonary disease (COPD) in Africa and of spirometry use to indicate the possibility of further unpublished data becoming shortly available.

Method  Literature review.

Results  Screening of 132 articles yielded 22 relevant articles, of which only six used spirometry based data. A total of 106 physicians in 34 countries were contacted and only 23 reported satisfactory use and availability of spirometry.

Conclusions  Current estimates of COPD burden in Africa are based on an unreliably small dataset. Acquisition of further data will require substantial investment in lung function equipment and training.

Abstract

La charge de la BPCO en Afrique - une revue de la littérature et étude prospective de la disponibilité de la spirométrie pour le diagnostic de la BPCO en Afrique

Objectifs:  Déterminer la charge de la BPCO en Afrique et l’utilisation de la spirométrie pour indiquer la possibilité de données supplémentaire non encore publiées mais disponibles prochainement.

Méthode:  Revue de littérature.

Résultats:  L’analyse de 132 articles a révélé 22 articles pertinents dont 6 seulement ont utilisé des données basées sur la spirométrie. 106 médecins dans 34 pays ont été contactés et seuls 23 ont rapporté une utilisation satisfaisante et la disponibilité de la spirométrie.

Conclusions:  Les estimations actuelles de la charge de la BPCO en Afrique sont fondées sur un petit nombre non fiable de données. L’acquisition de données supplémentaires nécessitera des investissements importants dans les équipements et la formation sur la fonction pulmonaire.

Abstract

La carga de EPOC en África – una revisión de la literatura y estudio prospectivo sobre la disponibilidad de espirometría para el diagnóstico de EPOC en África

Objetivos:  Establecer la carga conocida de la enfermedad pulmonar crónica obstructiva (EPOC) en África y el uso de espirometría para indicar la posibilidad de que datos no publicados estén pronto disponibles.

Método:  Revisión literaria.

Resultados:  El tamizaje de 132 artículos resultó en el hallazgo de 22 artículos relevantes, de los cuales solo 6 utilizaron datos basados en espirometrías. 106 médicos en 34 países fueron contactados, y solo 23 reportaron un uso satisfactorio y disponibilidad de la espirometría.

Conclusiones:  Las estimaciones actuales de la carga de EPOC en África están basadas sobre datos aunque no son confiables. La obtención de nuevos datos requerirá una inversión sustancial en equipos y entrenamiento para la medición de la función pulmonar.

Introduction

The most commonly used definition for chronic obstructive pulmonary disease (COPD) is that used by the global initiative for chronic obstructive lung disease (GOLD) as ‘a preventable and treatable disease…characterised by airflow limitation that is not fully reversible. The airflow limitation is usually progressive and associated with an abnormal inflammatory response of the lungs to noxious particles or gases’(GOLD 2008) This definition is rigorous, precise and requires spirometry.

Chronic obstructive pulmonary disease results in high mortality and morbidity worldwide. WHO states that COPD is the fifth and sixth cause of death in high income and low and middle income countries, respectively Lopez et al. (2006a,b). Mortality increases with decreasing lung function, due to acute cardiac events, infective exacerbations and acute respiratory failure (Murray et al. 2005). COPD can cause loss of function in multiple ways, including co-morbidities such as muscle weakness, weight loss, cardiac disease and depression (Murray et al. 2005). However, dyspnoea is the main reason for COPD having the 10th highest morbidity in low and middle income countries (Lopez et al. 2006a,b). The economic burden of COPD is high in developed countries due to healthcare and loss of productivity (Mannino & Buist 2007), but there are very few data available on mortality, morbidity or economic burden in developing countries (Chan Yeung et al. 2004).

Smoking is the main risk factor for COPD and exposure to occupational (Naidoo et al. 2005) or domestic fumes (Kiraz et al. 2003) and previous infection also cause the disease. Smoking levels have increased worldwide except in Europe and the Americas (Chan-Yeung et al. 2004) which may affect COPD prevalence worldwide. There is a high COPD prevalence due to indoor air pollution in middle income countries, particularly among women (Kiraz et al. 2003) which indicates that the COPD burden in Africa may be largely due to equivalent indoor air pollution in African homes (Norman et al. 2007). Rising smoking rates and high levels of tuberculosis infection (Ehrlich et al. 2004) may also increase the disease prevalence. Smoking cessation and avoidance of noxious fumes can prevent COPD onset and progression (Buist et al. 2007). Wealth and education are deemed protective (Ehrlich et al. 2004). Treatments include bronchodilators, corticosteroids, oxygen therapy and finally lung transplants (Murray et al. 2005).

We reviewed the burden of COPD in Africa, focusing in particular on prevalence data and the reliability of current estimates. We also carried out a telephone and e-mail survey of African physicians to estimate the current use of spirometry for the diagnosis of COPD in specialist centres.

Methods

Literature review

The databases ‘Ovid Medline’, ‘Embase’ and ‘EBV Reviews’ were searched using the search strategy summarised in Figure 1. Search terms used are shown in Table 1. Limits of ‘English’, ‘1996-week 1 2009’ were used but non-English language articles with English abstracts were also included. The search did not include articles published before 1996 to allow full online access and to reduce variability caused by earlier differences in COPD definitions. However, older articles were used when appropriate after manually sorting through references. The results were manually sorted, removing irrelevant and duplicate articles. Further articles were identified from references obtained in the primary search.

Figure 1.

 Search strategy.

Table 1.   Search terms
Search numberTerms used
  1. COPD, chronic obstructive pulmonary disease.

1Chronic obstructive lung disease
COPD
Chronic bronchitis
Emphysema
2Africa, Algeria, , Benin, Botswana, Burkina Faso, Burundi, Cameroon, Chad, Comoros, Cote d’Ivoire, Ivory Coast, Congo, Djibouti, Egypt, Equatorial Guinea, Eritrea, Ethiopia, Gabon, Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Lesotho, Liberia, Libya, Madagascar, Malawi, Mali, Mauritania, Mauritius, Morocco, Mozambique, Namibia, Niger, Nigeria, Rwanda, Senegal, Sao Tome Principe, Seychelles, Sierra Leone, Somalia, Sudan, Swaziland, Tanzania, Togo, Tunisia, Uganda, Zambia, Zimbabwe, Angola, Dahomey, Bechuanaland, Oubangui-Chari, Zaire, Afars, Issas, Abyssinia, Basutoland, Nyasaland, Ruanda-Urundi, Somaliland, Zanzibar, Tanganyika, Bugunda, Rhodesia
3Prevalence
Epidemiology
Incidence
4Aetiology
Risk Factors
5Management
Prevention

Survey of spirometry use for COPD diagnosis

We carried out the telephone and e-mail survey of African physicians. Pan African Thoracic Society (PATS) members and officers, and applicants to the PATS methods in epidemiological clinical operations research (MECOR) course 2008/2009 were contacted by e-mail and asked to take part in the survey. Forty-eight hours after the initial e-mail request, physicians who did not reply and whose mobile telephone contacts were available were sent a text message. Text messages were also sent to physicians without e-mail addresses, if mobile numbers were shown. Respondents participated in structured interviews using the questionnaire below:

  • Name, age.
  • In which country do you currently practise?
  • Medical specialty?
  • Do you routinely diagnose COPD?
  • If yes, how often in the past 12 months?
  • Have you requested pre- and post-bronchodilator spirometry testing in the last 12 months?
  • • What (if any) problems have you had with spirometry testing?

Results

Literature review

About 342 articles included COPD-related terms and the name of an African country (Appendix 1). Abstracts referring to studies with prevalence, risk factors, management or prevention of COPD were selected (n = 132). From these abstracts, 101 abstracts written in English papers were reviewed for relevance to the study questions. A total of 22 papers were included in the literature review, including English abstracts from Francophone literature (Appendix 1) as they discussed issues surrounding COPD or chronic bronchitis specifically (Tables 1 and 2).

Table 2.   Summary of articles for specific countries in Africa
CountryPopulation typeDiagnostic criteriaNumbers involvedStatistics (prevalence/mortality)Comments
  1. COPD, chronic obstructive pulmonary disease; FVC, full vital capacity; FEV, forced expiratory volume in one second.

Algeria (Douagui 2007)Whole populationLaunch of Global Alliance against Chronic Respiratory Diseases programme Unknown 
Botswana (Steen et al. 2004)Whole populationMonthly statistical summaries from all health facilities sent to Botswana Ministry of Health compiled into annual reports and analysed 0.7% inpatient deathsCOPD classified with asthma, making results unreliable. Methods for COPD diagnosis not standardised across country
Ethiopia (Mengesha & Bekele 1998)Factory workersFVC, FEV1/FVC ratio, and dust exposure measured. British Medical research Council Questionnaire used for clinical symptoms211 non-smokers21.8% dust exposed with chronic bronchitisIncreased risk of chronic bronchitis, chronic cough and decreased lung function in cotton and cement factories than tobacco or controls. Bronchodilators not used to differentiate between asthma and COPD
Morocco (Benouhoud et al. 2007) GP’s patientsAudit carried out to evaluate GP’s awareness of diagnosis and management of COPD   48.9% GP’s aware of international guidelines for diagnosis and management of COPD. 10.8% ordered spirometry. Therefore, exact prevalence unknown
Nigeria (Ezeonu & Ezejiofor 1999)Cement workersBiochemical parameters, including serum bicarbonate, compared in worker and control populations35 Raised serum bicarbonate does not indicate chronic bronchitis specifically. Limited and specific participants, therefore results are not generalisable. No clinical details gathered
Nigeria (Aghanwa & Erhabor 2001)Specific hospitalMental status of COPD compared to hypertensive and healthy patients30 of each Small study, giving no indication of prevalence, and unreliably showing burden due to increased psychiatric morbidity in COPD patients
Nigeria (Erhabor et al. 2002)Specific hospitalMortality reviewed for admissions to hospital between 1990 and 1999.161 admissions25.5% mortalityNot generalisable to whole population, but to this specific hospital
Nigeria (Erhabor & Kolawole 2002)Specific hospitalCOPD case notes reviewed for risk factors and clinical features.160 Although no prevalence data gathered, male sex, indoor pollution, and smoking were found to be risk factors. This is not generalisable to the whole county
South Africa (Reid & Sluis-Cremer 1996)White Gold MinersStandardised mortality ratios, based on information (ICD code) from death certificates.4925189% increase mortality due to COPDDeath certificates may be unreliable, due to problems with diagnosis, and classification by clerks
The interaction between smoking and dust in unknown
South Africa (Sitas et al. 2004)Mortality in 19981998 death notification forms analysed for smoking prevalence and cause of death534037% increased COPD mortality due to smokingVariations in smoking intensity not included
Unreliable death certificates, diagnosis and coding
South Africa (Ehrlich et al. 2004)Stratified population sampleAdults interviewed using the South African Demographic and Health Survey, for chronic bronchitis. Personal and exposure variable measured13 8262.3% men
2.8% women
Chronic bronchitis shows grade 0 COPD without airflow obstruction
Different risk factors for men and women could explain different prevalence rates. Although smoking high risk for both, occupational risks were found in men and rural residence and domestic fuel use in women
South Africa (Ayo-Yusef et al. 2007)Snuff using black womenInterview-administered questionnaire, using participants of the South African Demographic and Health Survey44645.3 % with chronic bronchitisBrand, past history and duration of snuff use not included
Chronic bronchitis does not give a true indication of COPD
South Africa (Girdler-Brown et al. 2008)Gold minersQuestionnaires, spirometry, vital status62413.5%Estimated rather than personal dust exposures used
Not generalisable to whole population
Sudan (Ballal 1986) Chromite ore minersFVC and FEV1/FVC ratio measured. British Medical Research Council Questionnaire used for clinical symptoms12226% chronic bronchitisNo significant lung function problems were found. Dust was thought to be the main reason for symptoms as there was no relationship with smoking
Tanzania (Mustafa et al. 1978)Sisal workersRespiratory symptoms, FVC and FEV1 measured in spinning and brushing departments16012% chronic bronchitis in spinningThis study is out of date but no other literature was found for Tanzania
Tunisia (Tabka et al. 1999) Grain workersLung function and respiratory symptoms measured in exposed vs. non-exposed subjects70 of eachHigher chronic bronchitis (34%) and obstructive impairment (47%) in exposedMethods for lung function testing unknown. Specific population study does not allow for generalisation of prevalence rates
Zimbabwe (Cookson & Mataka 1978)Specific townBritish Medical Research Council Questionnaire used97681.12%No association shown between chronic bronchitis and smoking and low smoking prevalence. However, population demographics and risk factors such as smoking may have changed considerably in since this study was published

The literature review showed that only two prevalence surveys based on randomly selected populations have been published in Africa, both in South Africa: chronic bronchitis symptoms were reported in 2.3% men and 2.8% women (Ehrlich et al. 2004). COPD defined using spirometry (stage 2 or higher) was reported in 22.2% of men and 16.7% of women in Cape Town (Buist et al. 2007). Studies on selected populations (e.g. factory workers, miners and snuff users) were available from Ethiopia (Mengesha & Bekele 1998), Nigeria (Ezeonu & Ezejiofor 1999), South Africa (Reid & Sluis-Cremer 1996; Ayo-Yusef et al. 2007; Girdler-Brown et al. 2008), Sudan (Ballal 1986), Tanzania (Mustafa et al. 1978) and Tunisia (Tabka et al. 1999). These showed highly variable prevalence rates ranging from 5.3% to 47%. About 43/53 African countries had no published data on COPD, and 52/53 had no data for the general population.

Survey of spirometry use for COPD diagnosis

About 238 e-mails were sent to PATS members and PATS MECOR applicants. About of 106 were thought to be received as e-mails did not bounce and of these 52 (49.5%) gave a response. Twenty-four (23%) gave full answers to the questionnaire, either by phone or e-mail, and 22 PATS-MECOR students gave written responses. There were a total of 46 responses. Sixty-three per cent of doctors were male, and although responders came from a variety of specialties, the majority were paediatricians or respiratory doctors (Figure 2). We received at least one reply from 36% of African countries (Figure 3). Nigeria, South Africa and Kenya had the highest response rates. Several countries had one or no doctors replying (Figure 4).

Figure 2.

 Specialties of responders.

Figure 3.

 Distribution of replies in Africa.

Figure 4.

 Doctors diagnosing COPD in Africa. Showing total number of replies, of which how many diagnose COPD and how many of these use spirometry.

A total of 76% of respondents reported diagnosing COPD and 62% used spirometry. The remaining 38% used clinical symptoms for diagnosis. In South Africa spirometry was always used for COPD diagnosis, but this was not the case for doctors in other parts of the continent. The majority of doctors (n = 34/74%) had a problem with spirometry testing (Figure 5) – the most common complaint was lack of availability of the test. In the absence of spirometry, clinical diagnosis using symptoms such as chronic cough; sputum production for more than 3 months over the past 2 years; and the shortness of breath was used. There were insufficient data to compare spirometry use in rural and urban centres.

Figure 5.

 Problems with spirometry.

Discussion

There is very limited published literature on COPD in Africa, despite substantial epidemiological evidence from populations with similar exposures (Kiraz et al. 2003) indicating that COPD may be a problem in the region. In addition to the significant burden of disease being currently under-diagnosed, the means to make the correct diagnosis is still largely unavailable.

Of the 22 articles relating to COPD in Africa, only six had spirometric data and of these only the BOLD study (Buist et al. 2007) measured lung function in a general population. The BOLD results were surprisingly high compared to previous estimates which predicted low COPD mortality in Africa (Lopez et al. 2006a,b).This could be because the BOLD study factored in risks such as smoking with more precision by using logistic regression. In studies on specific populations, there is a wide range of prevalence reported. This variation suggests that risk factors may vary between populations, but it is also likely that methods of data collection, diagnosis and vital statistics are not generalisable across the studies. We have not yet reviewed the French literature, but the PATS will be challenged to do this in the near future.

Careful interpretation of the initially encouraging statistics from our survey is necessary due to the low response rate and because our inclusion only of PATS members will inevitably over-report the availability of lung function testing. The inclusion of paediatricians, who do not routinely diagnose COPD due to the epidemiology of the disease, will bias the results further, giving a false indication of COPD diagnosis rates. The small number of respondents from such a vast continent gives an indication of the difficulty in data collection due to communication difficulties and the lack of resources, and gives weight to the worry that very little accurate data on COPD will emerge from Africa in the near future. The bias in number of physicians and countries from which data was reported also gives some indication of the low use of spirometry, as those with access to the equipment may be more likely to be involved in the study. This survey could be extended to include more doctors across each African country to get a better picture of spirometry use. However, it is unlikely that this would find many more spirometry users outside the centres reported here as these were some of the main urban and university hospitals where funding and knowledge of spirometers will pool. Alternative guidelines or methods of diagnosis specific to Africa might be developed to reliably assess the current burden of COPD, but this has already been demonstrated to be highly problematic in other regions of the world (GOLD 2008).

Table 3.   Summary of review papers
TitleEstimated prevalenceSummary
International variation in the prevalence of COPD (the BOLD Study): a population-based prevalence study (Buist et al. 2007)22.2% men and 16.7% women in Cape Town, South AfricaThis is not generalisable for the whole continent
Shows higher rates of COPD and smoking than other studies
Chronic obstructive pulmonary disease: current burden and future projections Lopez et al. (2006a,b)0.5% mortality in parts of AfricaDeath registration and cause of death categorisation is unreliable, and may lead to lower prevalence
Diagnosis based on clinical ‘self-reporting systems’ without spirometry
This is an estimate and based on limited data for Africa
The burden and impact of COPD in Asia and Africa. (Chan-Yeung et al. 2004)179/100 000
Thought to be lowest in world
COPD is more prevalent with age. This statistic does not account for Africa’s young population
There is a lack of epidemiological data for the whole continent, including national statistics and death registration
Risk factors, such as smoking rates, are estimated as low and increasing though are mainly unknown
Diagnostic error due to combination of asthma and COPD and lack of spirometry use
Management of chronic obstructive pulmonary disease in Asia and Africa (Chan-Yeung et al. 2004) It is thought that spirometry testing for diagnosis is not always possible due to unavailability. However, this is based on a few papers, and cannot be generalised for the whole continent
Management of chronic respiratory and allergic diseases in developing countries. Focus on sub-Saharan Africa (Bousquet et al. 2003)Chronic bronchitis: 3.5% in Algeria – 11% South AfricaImproved disease surveillance needed due to limited data

Conclusion

Chronic obstructive pulmonary disease is a global priority in high and middle income countries, but in Africa has features of a neglected disease (WHO 2006) being associated with poverty and limited access to healthcare (Enserink 2009). This indicates the need for further international investment into spirometry equipment and further research to enable specific guidelines to be developed.

Table Appendix1..   Search methods and numbers of articles found
1Africa OR Algeria OR Benin OR Botswana OR Burkina Faso OR Burundi OR Cameroon OR Chad OR Comoros OR Cote d’Ivoire OR Djibouti OR Egypt OR Equatorial Guinea OR Eritrea OR Ethiopia OR Gabon OR Gambia OR Ghana, Guinea OR Guinea-Bissau OR Kenya OR Lesotho OR Liberia OR Libya OR Madagascar OR Malawi OR Mali OR Mauritania OR Mauritius OR Morocco OR Mozambique OR Namibia OR Niger OR Nigeria OR Congo OR Rwanda OR Senegal OR Sao Tome and Principe OR Seychelles OR Sierra Leone OR Somalia OR South Africa OR Sudan OR Swaziland OR Tanzania OR Togo OR Tunisia OR Uganda, OR Zambia OR Zimbabwe OR Angola OR Dahomey OR Bechuanaland OR Oubangi-Chari OR Zaire OR Afars OR Issas OR Abyssinia OR Basutoland OR Nyasaland OR Ruanda-Urundi OR Somaliland OR Zanzibar OR Tanganyika OR Bugunda OR Rhodesia194 209
2Chronic obstructive lung disease OR COPD or chronic bronchitis OR emphysema53 030
3Prevalence OR epidemiology OR incidence583 662
4Aetiology OR risk factors636 207
5Management OR prevention979 912
61 AND 2342
76 AND 350
 6 AND 466
86 AND 563
96 OR 7 OR 8132
 Limits: English, human, 1996–2009
Abstracts reviewed
Articles were chosen for relevance to search terms, especially COPD and Africa, as many articles were not relevant in this review
Articles were included when no other data was available for the country. Articles for specific populations were removed when general population studies were available. When data on COPD for general populations was not available, any articles concerning emphysema or chronic bronchitis for general OR specific populations were included
101
10Articles reviewed (full paper)16
 Non-English 
117 limited to English44
127 not 11 (i.e. non-English)5
138 limited to English56
148 not 139
159 limited to English43
169 not 1519
 12 OR 14 OR 16
Abstracts reviewed
24
 Articles reviewed with English abstracts only3
 Reviews from references (1978, 1986)3
 Total selected papers22

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