The International Journal of Mycobacteriology

ORIGINAL ARTICLE
Year
: 2019  |  Volume : 8  |  Issue : 2  |  Page : 118--123

Determinants of pulmonary tuberculosis in public health facilities of Dire Dawa City, Eastern Ethiopia: Unmatched Case–control study


Jafer Kezali Hassen1, Andamlak Gizaw2, Shikur Mohamed2,  
1 Public Health Emergency Management, Ethiopian Public Health Institute, Addis Ababa, Ethiopia
2 Department of Public Health, Saint Paul's Hospital Millennium Medical College, Addis Ababa, Ethiopia

Correspondence Address:
Jafer Kezali Hassen
Ethiopian Public Health Institute
Ethiopia

Abstract

Background: The Federal Ministry of Health of Ethiopia Annual performance report in 2014–2015 showed that the highest prevalence of tuberculosis (TB) case in Ethiopia was reported from Dire Dawa city which was 400/100,000 population. The aim of this study was to identify the determinants of pulmonary TB (PTB) in public health facilities of Dire Dawa city, Eastern Ethiopia. Methods: A case–control study was conducted from October to December 2017 among 95 cases and 190 controls in Dire Dawa city. Dire Dawa is one of the two chartered cities in Ethiopia like the capital city Addis Ababa. Cases and controls were identified and selected randomly from the health facilities. Data were collected using a pretested and structured questionnaire by trained data collectors. We used logistic regression to model the associations of independent variables with PTB infection. Results: PTB was associated with patients' education (no formal education vs. formal education) (adjusted odds ratio [AQR] [95% confidence interval [CI]: 3.0, [1.3, 7.1]), human immunodeficiency virus (HIV) positive status (AOR [95% CI]: 3.1: [1.1,9.1]), previous contact history with TB patient (AOR [95% CI]: 9.9 [4.3,23.0]), body mass index (BMI) of ≤18 (AOR [95% CI]: 14.9 [6.4,35.1]), and cigarette smoking history (ever vs. never) (AOR [95% CI]: 6.7 [2.3,19.5]). Conclusion: This study showed that patients' educational status, HIV status, cigarette smoking, contact history with PTB patient, and BMI were independently associated with being infected with PTB. To reduce PTB transmission, peoples should be educated on TB prevention and consequences of risky behaviors.



How to cite this article:
Hassen JK, Gizaw A, Mohamed S. Determinants of pulmonary tuberculosis in public health facilities of Dire Dawa City, Eastern Ethiopia: Unmatched Case–control study.Int J Mycobacteriol 2019;8:118-123


How to cite this URL:
Hassen JK, Gizaw A, Mohamed S. Determinants of pulmonary tuberculosis in public health facilities of Dire Dawa City, Eastern Ethiopia: Unmatched Case–control study. Int J Mycobacteriol [serial online] 2019 [cited 2019 Oct 22 ];8:118-123
Available from: http://www.ijmyco.org/text.asp?2019/8/2/118/260384


Full Text



 Introduction



Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis. It typically affects the lungs of individuals (pulmonary TB [PTB]) but can have an effect on other sites as well (extra-PTB).[1] TB is more common among people infected with human immunodeficiency virus (HIV) and affects mostly economically productive age groups of the population.[1],[2] The African Region had 28% of the world's cases in 2014, but the most severe burden relative to population is 281 cases for every 100,000 people, more than double the global average of 133. According to the World Health Organization, Ethiopia is among the top ten high burden countries in terms of TB prevalence or incidence.[3],[4] The Federal Ministry of Health of Ethiopia Annual performance report in 2014–2015 showed that the highest prevalence of TB case was reported from Dire Dawa city which was 400/100,000 population.[5]

Movements to reduce the rates of TB must center on controlling transmission and identifying associated factors as a means of minimizing the overall burden of the disease. It has been observed that not all patients who have PTB transmit the disease; therefore, research must include an examination of specific determinant factors to show which influence and result in development of the disease without difference in the infection status.

PTB is a multifactorial disease in which sociodemographic, environmental, and individual factors contribute to the disease process.[6] Risk factors for TB identified in other similar studies include contact with a TB patient, poor socioeconomic factors, tobacco smoking, alcohol abuse, and HIV infection.[7],[8],[9],[10],[11] However, despite the high burden of TB infection in Dire Dawa city, the risk factors associated with PTB were not studied before. Therefore, the aim of this study was to identify factors associated with PTB among patients in public health facilities of Dire Dawa city.

Since Dire Dawa city reports the highest prevalence of TB case in Ethiopia in 2014–2015, the findings from this study will be beneficial to Dire Dawa City Administration Health Office and other stakeholders that offer TB diagnosis and treatment because identifying the determinant risk factors will help to improve programmatic importance implication and reduction of chain of transmission, and it can also be used as stepping board for those who will do further study on this area.

 Methods



Study design

Facility-based unmatched case–control study was conducted from October to December 2017 in public health facilities of Dire Dawa city administration.

Study setting

The study was conducted in Dire Dawa city administration, which is located in the eastern part of Ethiopia, which is 515 km away from Addis Ababa. Dire Dawa is one of the two chartered cities in Ethiopia, the other being Addis Ababa. It is precisely located between 90 28.1” N and 90 49.1” N latitude and between 410 38.1” E and 420 19.1” E longitude. There are two hospitals (Dilchora Referral Hospital and Sabian Primary Hospital) and eight health centers (Addis Ketema, Dechatu, Gende Gerada, Gende Kore, Goro, Dire Dawa, Melka Jebdu, and Legehare Health Center) in Dire Dawa city administration.

Source and study population

All adult patients who visited the public health facilities (2 hospitals and 8 health centers) of Dire Dawa city and all adult patients who attended the two hospitals and eight health centers of Dire Dawa city from October to December 2017 were the source and study populations, respectively.

Case definition and diagnosis procedures of cases and controls

Patients who registered as PTB at the TB clinic of the health facilities and aged above 15 years were selected as cases, and patients at outpatient department with no productive cough for at least 2 weeks previously and any sign and symptoms of PTB and aged above 15 years were selected as controls during the study period. Active PTB was diagnosed by smear microscopy with gene expert and radiological methods. Controls admitted with illness of the respiratory system were excluded from the study. Cases and controls were also excluded if they were unable to give an interview due to critical sickness or unconsciousness.

Sample size and sampling procedure

The sample size was determined using Epi-Info STATCALC software (CDC, USA) and using the following assumptions: power (80%), corresponding 95% confidence interval (CI) value from standard table (z = 1.96), controls to cases ratio (2:1), proportion of body mass index (BMI) <18.5 among controls (P = 41.8%), odds ratio (OR) of BMI <18.5 from previous studies in Ambo Hospital = 2.1.[12] With the Fleiss continuity correction, the sample size was set at 95 cases and 190 controls, with a total sample size of 285.

Cases were selected consecutively to the study until the required sample size was filled, whereas controls were selected using simple random sampling technique from the selected outpatient department of the ten health facilities from October to December 2017. The first two outpatient department attendees who were free from PTB and aged above 15 years following each case were selected as controls in the study.

Data collection and quality control

The questionnaire was developed in English after reviewing different literature[7],[8],[9],[10],[11] and translated to Amharic. Data were collected using an interviewer-administered questionnaire by trained physicians and nurses. Information was collected on a wide range of potential host-related and environment-related determinant factors for PTB. Host information included basic demographic data and behavioral factors, such as age, gender, occupation, educational status, marital status, place of residence, patient history of TB, family history of TB, HIV infection, smoking cigarette, alcohol intake, khat chewing, smoking shisha, employment, monthly income, and diabetes. The environmental factors included number of families living in the household (HH), person per room, housing condition, wall type, floor type, and presence or absence of windows. A beam balance scale with a height measuring scale was used to measure height and weight of the participants. The questionnaire was pretested in 5% of the total sample size at three private hospitals of Dire Dawa city administration, and revision was made accordingly. One-day training was given for the data collectors, and close supervision during data collection was made as quality control measures.

Data management and analysis

The data were entered into Epi-Info7 software (CDC, USA) and finally analyzed using IBM Statistical Package for the Social Sciences (SPSS) version 21 (SPSS Inc., Chicago, USA). Descriptive statistics were computed to describe the distribution of various characteristics of cases and controls. To identify the determinants of PTB: first, a binary logistic regression analysis was conducted to select the candidate variables, with a P < 0.1, for multiple logistic regression analysis. Then, multiple logistic regressions were used, to compute adjusted OR (AOR) with 95% CI, to identify the independent predictors of PTB. Statistical significance was set at α ≤ 0.05.

Ethical considerations

Ethical approval and clearance was obtained from the Institutional Review Board of St. Paul's Hospital Millennium Medical College. At all levels, officials were contacted and permission from administrators was secured. All the necessary explanation about the purpose of the study and its procedures was explained to the study participants with the assurance of confidentiality. Written and verbal consent from the study participants was secured.

 Results



Sociodemographic characteristics of the respondents

In this study, a total of 285 participants (95 cases and 190 controls) were included and all participated. The mean age was approximately 33 (standard deviation [SD] ±13) years and 33 (SD ± 13) years for cases and controls, respectively. Productive age group (15–44) comprised 78 (82.1%) of the total cases. Forty-six (48.4%) cases and 115 (60.5%) controls were married [Table 1].{Table 1}

Behavioral and health-related factors

Majority of cases 79 (83.2%) were underweight (BMI <18.5) whereas only 29 (15.3%) of controls were underweight. Twenty-three (24.2%) cases and 8 (4.2%) controls had a history of contact with TB patients, respectively. Approximately 54% of cases and 17% of controls had a family history of TB. Thirty-three percent (32.6%) of cases and 10% of controls were cigarette smokers. Approximately, 40% of cases and 6% of controls were infected with HIV infection [Table 2].{Table 2}

Environmental-related factors

Majority of cases (57, 60%) lived in a compound which had more than two HHs, and similarly, 69 (36.3%) of controls lived in a compound which had more than two HHs. Approximately, 75% of cases and 21% of controls lived in a house of mud wall [Table 3].{Table 3}

Independent determinants of pulmonary tuberculosis

During multivariable logistic regression analysis of sociodemographic, behavioral, and environmental-related factors, patient educational status of no formal education, being HIV positive, being cigarette smoker, having contact history with PTB patient, and being underweight were found associated with PTB. Patients who had no formal education were three times more likely to develop PTB than those who had a formal education (AOR: 3.0; 95% CI, 1.3–7.1). According to this study, people living with HIV were three times more likely to develop PTB compared to people who were free from HIV/AIDS (AOR: 3.1; 95% CI: 1.1–9.1). Similarly, people who had a history of contact with TB patients had ten times more likely to develop PTB than those with no contact history (AOR: 9.9; 95% CI: 4.3–23.0). Patients who had a BMI of <18.5 were 15 times more likely to develop PTB compared to those who had BMI >18.5 (AOR: 14.9; 95% CI: 6.4–35.1). Furthermore, patients who smoked cigarette were approximately seven times more likely to develop PTB compared to their counterparts (AOR: 6.7; 95%CI: 2.3–19.5) [Table 4].{Table 4}

 Discussion



In this study, educational status, smoking cigarette, contact history, low BMI, and HIV-positive status were significantly associated with the occurrence of PTB in Dire Dawa city, Eastern Ethiopia.

The findings from the current study showed that patients who had no formal education were three times more likely to develop PTB compared to their counterparts. This was in line with the studies conducted in Metema, Northwest Ethiopia; Bangalore, South India; and Croatia where people with no formal education were more likely to develop the disease than those with higher education.[11],[13],[14] This might be because people who do not have formal education are not aware of the disease causative agent and mode of transmission which may increase their probability of acquiring the disease.

According to the current study, people living with HIV were three times more likely to develop PTB compared to people who were free from HIV/AIDS, which is consistent with previous studies conducted at Ambo Hospital, Western Ethiopia, and in Malawi.[12],[15] A study conducted in Guinea Bissau, Gambia,[16] showed that being HIV positive was significantly associated with PTB. This might be because decreased immunity in HIV-infected persons may increase risk of reactivation of latent TB.

The findings of the current study showed that people with a history of contact with TB patients had ten times more likely to develop PTB compared to those with no contact history. This finding is consistent with the studies conducted at Metema District Hospital, Northwest Ethiopia;[13] Malawi;[15] at Semarang district, Indonesia;[17] in three major tertiary hospitals of Pakistan;[18] and in Croatia[14] which all showed that people who had a history of contact with TB patient were more likely to develop PTB.

The current study revealed that underweight (BMI <18.5) people were more likely to develop PTB compared to their counterparts, which is consistent with previous studies conducted at Ambo Hospital, Western Ethiopia,[12] and Croatia.[14]

The findings of the current study showed that cigarette smokers were more likely to develop PTB compared to people who do not smoke cigarette. This is in line with other studies conducted at Ambo Hospital, Western Ethiopia;[12] in West Africa;[16] in Semarang District, Indonesia;[17] and in Croatia[14] which showed that being cigarette smoker was significantly associated with PTB. This study has all the weakness associated with a case–control study design. The first weakness is that recall bias is inbuilt to case–control studies. Recall can be contradictory with cases being more likely to remember exposures as compared with controls. However, in this study, cases and controls were patients in the same health facility; therefore, it is likely to reduce this effect. The other main limitation was that the controls were not tested using laboratory procedures with the same as cases to establish their PTB status, they were recruited only by history of cough, and however, we excluded patients with any respiratory disease to minimize selection bias.

 Conclusion



In this study, patient educational status of no formal education, being HIV positive, being cigarette smoker, having contact history with PTB patient, and being underweight were found significantly associated with patients' development of PTB. Therefore, community-based health education on PTB mode of transmission and prevention strategies should be given exhaustively by concerning stakeholders including by the community health extension workers. Behavioral change communication strategies to cease smoking and discourage smoking should be designed and implemented through different means. New PTB patients should be educated by the health professionals and health extension workers on how to reduce contact with healthy individuals in their family and community just to reduce the transmission of the disease. Efforts should be made to reduce incidence of PTB among HIV patients by health professionals by strengthening Anti-Retroviral Treatment (ART) care services.

Acknowledgment

We would like to acknowledge St. Paul's Hospital Millennium Medical College for their funding support to this study. We are grateful to all TB focal personnel in each health facilities for their support during the data collection.

Financial support and sponsorship

We got financial support from St. Paul's Hospital Millennium Medical College.

Conflicts of interest

There are no conflicts of interest.

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