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 Table of Contents  
Year : 2020  |  Volume : 18  |  Issue : 3  |  Page : 241-246

Survey of undiagnosed airflow limitation among cardiac and diabetic patients in a Nigerian teaching hospital

1 Department of Physiotherapy, School of Health Sciences, College of Medicine, Suva, Fiji Islands
2 Department of Physiotherapy, College of Medicine, University of Ibadan, Ibadan, Nigeria

Date of Submission10-Sep-2019
Date of Decision09-Dec-2019
Date of Acceptance02-Jun-2020
Date of Web Publication30-Oct-2020

Correspondence Address:
Ayodele A Akinremi
School of Health Sciences, College of Medicine, Nursing and Health Sciences, Fiji National University, Hoodless House, Brown Street, Suva, Postal/Zip Code: 000
Fiji Islands
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/AZMJ.AZMJ_124_19

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Background Airflow limitation is associated with all-cause mortality and could worsen treatment outcomes in chronic diseases. In resource-limited countries, where availability of spirometry facilities poses a major challenge, the magnitude of airflow limitation among patients with chronic diseases is unknown. Such information may justify the need for routine lung function screening, early detection, and management of airflow impairment among this population.
Objective This study aims to estimate the magnitude of airflow limitation among patients attending endocrinology and cardiology clinics in a tertiary healthcare facility in south-western Nigeria.
Patients and methods A cross-sectional survey design study was performed, involving individual with diabetes and hypertension who were recruited from the outpatient unit of the hospital. A handheld digital spirometer was used to measure lung function indices. Data were analyzed using descriptive statistics of mean, SD, frequencies, and percentages. c2 test was used to test for difference in proportions between sexes and patient groups.
Results A total of 124 (90 females and 34 males) patients, comprising of 53 patients with diabetes, 67 with hypertension, and four with both diabetes and hypertension, participated in this study. Overall, 91 (73%) participants had airflow limitation: 52 (78%) of 67 hypertensive patients and 36 (68%) of the 53 patients with diabetes. Airflow limitation was significantly higher among men (94%) than women (66%). Severity of airflow limitation was as follows: 61 mild cases, 28 moderate, and two severe cases, which were undetected and untreated among the study population.
Conclusion Airflow limitation is common among the study population. Strategies aimed at early detection through routine lung function screening may be beneficial.

Keywords: airflow limitation, cardiovascular diseases, diabetes, lung function, southwest Nigeria

How to cite this article:
Akinremi AA, Sobande KK, Hamzat TK. Survey of undiagnosed airflow limitation among cardiac and diabetic patients in a Nigerian teaching hospital. Al-Azhar Assiut Med J 2020;18:241-6

How to cite this URL:
Akinremi AA, Sobande KK, Hamzat TK. Survey of undiagnosed airflow limitation among cardiac and diabetic patients in a Nigerian teaching hospital. Al-Azhar Assiut Med J [serial online] 2020 [cited 2023 Mar 22];18:241-6. Available from: http://www.azmj.eg.net/text.asp?2020/18/3/241/299565

  Introduction Top

In resource-limited hospital setting with limited or no spirometry facility, airflow limitation is often misdiagnosed or undiagnosed [1]. Undiagnosed airflow limitation often progresses, resulting in poor treatment outcomes, reduced functional status and quality of life [2], and may also complicate severity of other comorbidities [2]. Early detection and prompt management could improve clinical and functional outcomes among patients at risk. There is no evidence of data on how common is airflow limitation among individuals with chronic disease in this environment. Hence, this study was designed to evaluate the magnitude of airflow limitation among individuals with hypertension and diabetes in a tertiary healthcare center with limited lung function testing facility. The findings of this study inform the need for resource allocation for spirometry and also justify the need for routine screening among patients with chronic diseases.

  Patients and methods Top


A total of 124 individuals attending diabetic and cardiology clinics in a tertiary healthcare facility in south-western Nigeria participated in this study (90 females and 34 males).

Inclusion/exclusion criteria

Consenting adult patients (>18 years), without a history of recent head, thoracic, and abdominal surgery, attending the outpatient cardiology and diabetic clinics in a tertiary hospital in south-western Nigeria participated in this study. Individuals receiving treatment for any respiratory disease, or those with contraindication to spirometry, as well as current smokers or those who smoked within the past 5 years were excluded from this study.

Sample size

To detect a standardized difference of 0.25 in proportions of airflow limitation between patients with diabetes and cardiovascular diseases, with a power of 80%, a minimum sample size of 50 is required for each group.

Study design

The study was a cross-sectional survey design.

Study venue

The study was conducted in the cardiology and diabetic outpatient clinics in a tertiary healthcare center in south-western Nigeria from May to November 2015.

Ethical approval and data collection procedure

Ethical approval was sought and obtained from the Institutional Health Research Ethics Committee. The nature, purpose, and procedure of the research were explained to the prospective participants. Written informed consent was obtained from prospective participants. The participants were informed of their freedom to refuse to take part in the study and their right to withdraw at any given time they choose to. They were also assured of their confidentiality throughout the study.

Health records of all patients were accessed, and all individuals who met the selection criteria were recruited into the study for a period of 3 months. Participants’ demographic data of age, sex, medical diagnosis, and smoking history were obtained and recorded. Measurements of weight, height, forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), forced expiratory ratio (FER), and peak expiratory flow (PEF) were taken and recorded. FER was obtained as follows: FEV1/FVC.

Spirometry procedure

The procedure was explained and demonstrated to each participant. Participants were comfortably seated; the participants made a maximal inspiratory effort with the lips tightly closed around the mouthpiece of the portable spirometer and exhaled forcefully and continuously for about 6 s through the mouthpiece into the spirometer [3]. A minimum of three acceptable trials with FEV1 and FVC within 100 ml from each other was taken. At least 30 s of rest was allowed between successive spirometry maneuvers. The highest FEV1, FVC, FER, and PEF were recorded and analyzed [4]. Spirometry measurements were taken by trained personnel with spirometry certification. Quality of measurement was assured using biologic control and calibration after every eight measurements. Airflow limitation was defined as FEV1 less than 80% of percentage predicted [5]. Grading of severity is shown in [Table 1].
Table 1 Severity of any spirometric abnormality [6] based on forced expiratory volume in 1 s

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Statistical analysis

Continuous variables of age, BMI, FEV1, FVC, FER, and PEF were summarized using mean and SD, whereas categorical variables of sex, presence, and severity of airflow limitation were summarized with frequency and percentage in each category. c2 test was used to test for difference in proportions between sexes and patient groups.

  Results Top

Most (124) participants were never-smokers, whereas two male participants were former smokers; the last time they smoked was 10 and 11 years ago, respectively. All the individuals attending the cardiac clinic were managed for hypertension only. Most participants were artisans (61.3%). Others were civil servants (20.2%), clergy (2.4%), pensioners (12.9%), students (2.4%), and farmers (0.8%). The individuals with diabetes were similar to those with hypertension in age, body stature, and lung function indices (Appendix 4: [Table 2]).
Table 2 Physical characteristics and lung function of participants (N=124)

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Overall, 73% of all participants had lung function suggestive of airflow limitation. A similar magnitude was also noted within each disease category, with the hypertensive patients having significantly higher proportion (77%) (Appendix 5: [Table 3]). [Figure 1] (Appendix 1) shows the distribution of airflow limitation among study participants by disease and by sex. Among the participants with diabetes only, 10 males and 26 (29%) females were observed to have airflow limitation, whereas among those with hypertension only, 22 males and 30 females (42%) had airflow limitation. In the four participants who had both diabetes and hypertension, three had lung function suggestive of airflow limitation. In general, though more female participants (59) had airflow limitation compared with 32 among the males, the males had significantly higher proportion with airflow limitation (Appendix 5: [Table 3]).
Table 3 Proportion of participants with airflow limitation (N=124)

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Figure 1 Distribution of airflow limitation among study participants. AFL, airflow limitation; no AFL, no airflow limitation.

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Severity of airflow limitation among participants is presented in [Figure 2] (Appendix 2). From the 91 cases of airflow limitation observed in this study, two participants with hypertension had severe airflow limitation. A total of 61 cases of mild airflow limitation were observed among participants: 25 among diabetic patients and 35 among hypertensive patients. Overall, 28 cases of moderate airflow limitation were noted: 15 among individuals with hypertensive, 11 among diabetic patients, and two in patients with both hypertension and diabetes.
Figure 2 Classification of severity of airflow limitation of participants (n=91).

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  Discussion Top

This study was carried out to investigate the prevalence of airflow limitation among patients with diabetes and hypertension attending diabetic and cardiology clinics in a tertiary healthcare facility in south-western Nigeria. Age of participants ranged from 48 to 78 years, with overall average of 57 years; hypertensive and diabetic patients were similar in age. Age has been reported to significantly affect lung function [7]; this may explain the generally low lung function indices of participants. The total number of participants from cardiology clinic was 67, endocrinology clinic was 53, and participants attending both clinics were four. In the study population, there were more females than males. This may be a reflection of the higher prevalence of diabetes and cardiac disease among females in Nigeria [8]. Natural decline in lung function associated with age and the sex variability was taken care of by comparing an individual’s spirometric measurement with percent predicted for age, sex, and height. Airflow limitation is significantly higher among men (94%) compared with women (65.5%).

Participants’ lung function indices

The findings of this study showed a high proportion of participants had very low lung function values compared with the percentage predicted for age, height, and sex. It has been suggested that chronic noncommunicable diseases such as cardiovascular disease, diabetes, and metabolic disorder adversely affect lung function parameters, which may present as obstructive impairment [9].

Prevalence of airflow limitation among participants

This study showed that the prevalence of airflow limitation was 73.4%: 91 participants comprising of 59 females, 32 males. The prevalence of airflow limitation among hypertensive patients was 42% (52 out of 124 participants). This finding is similar to the report of Mannino et al. [10]. They investigated the prevalence and outcomes of diabetes, hypertension, and cardiovascular disease in COPD and reported a prevalence of 40% among patients who are hypertensive. Our finding was also corroborated that of Dhungel et al. [11], who observed a prevalence of 41% hypertension in patients with chronic obstructive pulmonary disease admitted at Nepal Medical College and Teaching Hospital. The prevalence of airflow limitation among participants with diabetes (29%) in this study was similar to that reported by Shunsuke et al. [9], which estimated prevalence of airflow limitation in diabetic patients to be 29.8%.

It is increasingly recognized that airflow limitation involves several systemic features, particularly in patients with severe disease, and these have a major effect on survival [12]. Airflow limitation is not a single-organ condition, but it is associated with multiple morbidity, such as cardiovascular disease, metabolic syndrome, skeletal muscle dysfunction, and osteoporosis [12]. These chronic diseases share common risk factors such as smoking, aging, physical inactivity, and unhealthy diet [13]. It has been suggested that the lungs, bone marrow, and adipose tissue are major components of an interconnected network that channels and facilitates biological interactions in response to inhalation particles from smoking and other sources of air pollution; airflow limitations have significant pulmonary and extrapulmonary effects [14]. The extrapulmonary effects, which include weight loss, nutritional abnormalities, and skeletal muscle dysfunction [2], increase the risk of myocardial infarction, angina, osteoporosis, respiratory infection, bone fractures, depression, diabetes, sleep disorders, anemia, and glaucoma [13].

It has been suggested that inhalation of particles and gases in genetically susceptible individuals results in enhanced and persistent inflammatory response in the lungs and other physiological systems [14]. Pathological changes characteristics of airflow limitation are found in the proximal airways, peripheral airways, lung parenchyma, systemic endothelium, and pulmonary vasculature [15]. The lung parenchyma orchestrates an inflammatory response through the release of inflammatory mediators that can act both locally and at a distance. As such, they act as a first rapid defensive line, recruiting inflammatory effector cells to the lung parenchyma [16]. The extent of inflammation, fibrosis, airway hyperresponsiveness, and luminal exudates in small airways is correlated with reduction in FEV1, FVC, and FER [15].

There is increasing attention on inter-organ interactions in chronic diseases, particularly between the heart and lungs [17],[18]. De Blois et al. [19] reported that the presence of airflow limitation as a comorbidity was associated with poor prognosis in patients with heart failure. Patients with airflow limitation also have higher rates of cardiac and noncardiac mortality [20]. Furthermore, patients with airflow limitation often experience other concomitant disorders, such as cardiovascular diseases and metabolic disorders, which significantly impairs their health status and prognosis [21]. Impaired pulmonary function is not only a simple reflection of airflow limitation or reduced pulmonary capacity but may also be a marker of premature death [22].

Most of the airflow limitation observed were mild (61%), whereas 28% were moderate. Another major finding of this study is that all participants with airflow limitation in this study were previously unaware and hence untreated. Undetected and untreated airflow limitation could worsen in severity, progressing from mild to moderate to severe, further compromising the overall health of the patients. Without adequate strategy to address airflow limitation among this population, the magnitude may remain high and consequently contribute to future burden of chronic airway disease.

Strength and limitation

There is very sparse data on lung function of patients with chronic diseases in resource-limited healthcare settings where there is little or no facility for lung function testing. This is one of the emerging evidences from this environment showing that airflow limitation is common among this patient population, and mostly undetected or misdiagnosed. These findings highlight the need for routine lung function screening among diabetic and hypertensive patients for early detection and management of airflow limitation. We noted, however, that this study did not take into consideration the onset of disease among participants. This could have implications on the severity of airflow limitation observed in this study. Owing to inadequate resources, we were also unable to conduct reversibility testing, hence the findings are only suggestive of physiological limitation of the airway and cannot accurately ascertain the presence of an airway disease. Nonetheless, participants were informed about the outcome of the measurements, and those with findings suggestive of airway limitation were counseled to seek further help from their physician.

  Conclusion Top

Airflow limitation is common among study population and is more among cardiac and male participants. Severity of airflow limitation varies among study participants with a high proportion having mild airflow limitation. All participants with airflow limitation in this study were previously unaware and thus not receiving any medical care for its management. Individuals with airflow limitations were referred to further screening and management by their physician. Routine lung function screening should be conducted for all diabetic and hypertensive patients in the study settings for early detection and management of airflow limitation. This could possibly improve the treatment outcome among this population.


The authors would like to acknowledge all Pan-Africa Thoracic Society-Methods in Epidemiological Clinical and Operation Research (PATS MECOR), faculty and staff. The concept and proposal outline for the study was developed during the PATS MECOR training program in Limuru, Kenya in 2014 as a level 2 fellow. I would also like to acknowledge the Nursing and Health Record staff of the Medicine Out-patient Department of University College Hospital, Ibadan, Nigeria for their support in recruiting patients for this study.

Financial support and sponsorship


Conflicts of interest

There are no conflicts of interest.

  References Top

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  [Figure 1], [Figure 2]

  [Table 1], [Table 2], [Table 3]


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