The clinical characteristics of tuberculosis and associated co-morbidities among the elderly compared to adults in Dar es salaam, Tanzania

Abstract

Background: Due to a number of factors life expectancy and the proportion of men and women of 60 years and above continue to increase both globally and locally. Old age has been shown to be associated with impaired immunity (immunoscenensce), increased risk of co-morbidities such as diabetes mellitus, impaired renal function, poverty and malnutrition; factors which increase the risk of developing clinical Tuberculosis. Studies from Europe and America suggest that TB in the elderly often presents with atypical symptoms or atypical radiological findings or both. Furthermore the presenting clinical features may be confused with age related illnesses and hence delay TB diagnosis and treatment with consequent increased morbidity and mortality. The aim of this study was to describe the key characteristics of tuberculosis among the elderly and the associated co-morbidities and compare them to those of adults. Broad Objective: To describe and compare the clinical characteristics of tuberculosis and associated factors among patients aged 18-59(adults) and those aged 60 years or more (elderly) attending TB clinics in the city of Dar es salaam. Specific Objectives: (1) To describe and compare clinical characteristics of TB in the elderly and adults aged 18-59 years. (2) To determine and compare the sputum microscopy yield for Mycobacterium tuberculosis in elderly and adults with pulmonary TB (PTB). (3) To compare the chest radiological findings in elderly and adults aged 18-59 years with TB (4) To document the treatment outcomes at the end of intensive phase in the two groups (5) To describe and compare the co morbidities associated with TB in the two groups. Methodology: This was a hospital based prospective cohort study among TB patients aged ≥18 years attending TB clinics in three district hospitals of Dar es Salaam city. All the TB suspects attending the clinics between 2nd August 2014 to 31st December 2014 were investigated as per the NTLP diagnostic algorithm. Patients who consented were asked to provide blood samples for full blood count, random blood sugar, serum creatinine and HIV serology. At the end of two month of intensive therapy study subjects underwent repeat examinations of sputum for AFB, FBC, serum creatinine, CXR and weight. Adverse effects to drugs and mortality were also compared between the two groups. The estimated sample size for this study was 250 patients with TB. Results: We recruited 150 (59.3%) and 103 (40.7%) adults and elderly patients respectively. The mean age (SD) for the adults was 35.57 (± 10.3) and it ranged from 18 – 59 years. The mean age (SD) for the elderly was 67.17 (± 6.43) and it ranged from 60 – 90 years. Clinically adults were more likely to present with hemoptysis compared to elderly (23.4% Vs 8.3% p=0.006) while elderly were more likely to present with general body malaise compared to adults. (41.3% Vs 75.7%, p<0.001). Adults had a higher yield for Mycobacterium tuberculosis compared to elderly. (p<0.001). Radiologically a higher involvement of lower zone was observed in a larger proportion of elderly as compared to adults (42.3% Vs 18.5% p<0.001) while adults were more likely to form cavities (50.4% Vs 22.7% p<0.001).Elderly patients were more likely to present with poor treatment outcomes as compared to adults. Co morbidities such as obesity, hypertension, diabetes mellitus and renal insufficiency were observed more among elderly as compared to adults. The mortality rate was higher among elderly as compared to adults. (17.5% Vs 6.7 %, p<0.01) Conclusion: HIV infection was found to be an important risk factor for TB to both adults and elderly patients in Dar es Salaam. Atypical clinical and/or radiological findings, co-morbidities were significantly more common among the elderly compared to adults.