Introduction

Acute and chronic respiratory complications are common in patients with sickle cell anemia (SCA) and may cause significant comorbidities. The burden of chronic respiratory impairment among patients with SCA in sub-Saharan Africa is largely unknown. Adding a low-cost and easy-to-learn test such as spirometry to comprehensive care programs for patients with SCA may be feasible in sub-Saharan Africa. This could be a cost-effectiveness measure in the long-term because it would facilitate earlier identification of patients with the most severe respiratory diseases who require a more aggressive therapeutic approach to limit the incidence of lung end-organ disease, which is associated with increased mortality.1 

Methods

A collaborative program between Evelina London Children’s Hospital (London, United Kingdom), University of Udine (Udine Italy), and the Barau Dikko Teaching Hospital (Kaduna State University, Kaduna, Nigeria) was finalized to build capacity for comprehensive care for patients with SCA in northwest Nigeria. A respiratory follow-up program was set up in Kaduna that provided local health care personnel with training and the necessary equipment for spirometry. In March 2017, a European medical doctor skilled in lung function tests (M.A.) spent 3 weeks in Kaduna to help set up the respiratory follow-up program.

A portable spirometer (Easy On-PC; ndd Medical Technologies, Zurich, Switzerland), based on an ultrasonic flowmeter that meets the American Thoracic Society and European Respiratory Society requirements and does not require daily calibration, was donated to the Barau Dikko Teaching Hospital, together with a tablet that can be used to perform lung function tests with the Easy On-PC software. In addition, 1000 spirettes for spirometry were donated.

There was 1 day of teaching on the theoretical aspects of spirometry and respiratory impairment in patients with SCA for the health care personnel involved in patient follow-up. After the teaching session, hundreds of patients with SCA and healthy participants in schools were tested during 15 working days by M.A. and the doctors in charge of providing follow-up for pediatric patients (R.Z.) and adult patients (L.G.D.). Four young local doctors and some local nurses also helped collect data and received training on spirometry. During data collection, M.A. supervised local doctors while they performed spirometry tests, trained them, and discussed the interpretation of the resulting flow-volume curves in light of the medical history of each patient.

Results

A total of 186 patients with SCA and more than 400 healthy children age 5 to18 years were recruited. Low-quality spirometry tests were eliminated for the final analysis.

Assessments

Each participant underwent spirometry and anthropometry measurements. Parents of the patients were interviewed by local doctors who used a questionnaire that investigated the following:

  1. History of asthma

  2. Previous acute chest syndrome or stroke

  3. Number of pain crises lasting more than 24 hours in the last year

  4. History of fatigability

  5. Socioeconomic status

  6. Smoke exposure

  7. Type of fuel used for cooking at home

  8. Any other comorbidity apart from those depending on SCA.

For patients who were diagnosed with asthma, their parents received written instructions about managing acute asthma attacks along with a free supply of asthma medications (inhaled salbutamol and corticosteroids, a spacer, and written and simple graphic instructions about how to perform the puffs and clear therapeutic indications).

A database was created of all patients with SCA who underwent lung function testing; it included a hospital ID, data about spirometry results, and medical history. This database will be updated during future respiratory follow-up visits and will permit evaluation of the longitudinal trend in the lung function of patients included in the database. A printed version of each spirometry test report was stored for the future.

A clinical report was produced for each patient that indicated spirometry results and their critical interpretation, timing for repeating spirometry, and whether the patient needed any further diagnostic work-up based on the severity of respiratory impairment.

A collaboration between the coordinating center in the United Kingdom and the local hospital in Kaduna was maintained, and Nigerian doctors could send a PDF version of spirometry tests by e-mail whenever a second opinion for interpretation of spirometry might be required.

Spirometry results

Spirometry results were expressed as z scores according to the Global Lung Initiative 2012 predictive equations for African Americans. Lung function of Nigerian patients with SCA was compared to that of patients of sub-Saharan African origin with the same condition and age range who were in follow-up at the Evelina London Children’s Hospital (Table 1). Spirometry tests at Evelina London Children’s Hospital were performed with the same spirometer as that used in Kaduna. Children and adolescents with SCA in Nigeria showed remarkably lower spirometry and anthropometry indices than their counterparts in the United Kingdom (Table 1), with a much higher prevalence of a restrictive spirometry pattern (29.9% [46 of 154] in Nigeria; 10.7% [8 of 75] in the United Kingdom), suggesting higher prevalence of restrictive lung disease, which can result in end-organ lung damage. Throughout data collection, the 2 local doctors in charge of follow-up for patients with SCA learned to perform good-quality spirometries and to critically interpret them.

Table 1.

Anthropometry and spirometry z scores in patients with SCA from the United Kingdom and Nigeria

SCAMean difference between United Kingdom and Nigeria
United KingdomNigeriaMean difference95% CI
No. of males (%) 75 (54) 154 (54)   
Age, y 11.7 (2.8) 11.4 (3.2) 0.3 –0.5 to 1.1 
z score     
 Height 0.19 (1.25) –1.77 (1.21) 1.96 1.62 to 2.3 
 BMI 0.11 (1.17) –1.38 (1.34) 1.50 1.13 to 1.87 
 FEV1 –1.08 (1.03) –1.38 (0.96) 0.29 0.02 to 0.56 
 FVC –0.70 (1.01) –1.21 (0.96) 0.51 0.24 to 0.78 
 FEV1/FVC –0.89 (0.90) –0.47 (0.98) –0.41 –0.64 to –0.17 
SCAMean difference between United Kingdom and Nigeria
United KingdomNigeriaMean difference95% CI
No. of males (%) 75 (54) 154 (54)   
Age, y 11.7 (2.8) 11.4 (3.2) 0.3 –0.5 to 1.1 
z score     
 Height 0.19 (1.25) –1.77 (1.21) 1.96 1.62 to 2.3 
 BMI 0.11 (1.17) –1.38 (1.34) 1.50 1.13 to 1.87 
 FEV1 –1.08 (1.03) –1.38 (0.96) 0.29 0.02 to 0.56 
 FVC –0.70 (1.01) –1.21 (0.96) 0.51 0.24 to 0.78 
 FEV1/FVC –0.89 (0.90) –0.47 (0.98) –0.41 –0.64 to –0.17 

Results are mean (standard deviation), unless otherwise specified.

BMI, body mass index; FEV, forced expiratory volume; FEV1, volume of air that can be forced out in 1 second after taking a deep breath (an important measure of pulmonary function); FVC, forced vital capacity.

Conclusion

A 3-week training period with hundreds of spirometry tests performed under the supervision of an experienced operator was sufficient to provide local doctors in Kaduna, Nigeria, with the needed skills to use spirometry tests to continue follow-up of their patients with SCA. The equipment and utilities necessary to continue respiratory follow-up were provided by a coordinating center in the United Kingdom.

Lung function assessment in pediatric Nigerian patients revealed a more severe respiratory impairment compared with assessments of their counterparts in the United Kingdom. This highlighted the importance of introducing spirometry assessment and follow-up in African patients with SCA to detect patients at risk of lung end-organ disease who are eligible for more aggressive therapies.

Authorship

Conflict-of-interest disclosure: B.P.D.I. served as a consultant for AstraZeneca and received honoraria, served on the Speakers Bureau, and received research funding from Novartis. The remaining authors declare no competing financial interests.

Correspondence: Ramatu Aliyu Zubair, Department of Pediatrics, Barau Dikko Teaching Hospital, Kaduna State University, Kaduna, Nigeria; e-mail: ramatuz@yahoo.co.uk.

Reference

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