A 4 Year Analysis of Seasonality and Trends of Tuberculosis from 2016 to 2019 at a Tertiary Care Center in North Delhi

Ahmad N

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OJHAS Vol. 20, Issue 2: (April-June 2021)

Original Article
A 4 Year Analysis of Seasonality and Trends of Tuberculosis from 2016 to 2019 at a Tertiary Care Center in North Delhi.

Authors:
Nadeem Ahmad, Assistant Professor, Department of Microbiology, University College of Medical Sciences and GTB Hospital, Delhi,
Sanjay Jain, Head, Department of Microbiology, North DMC Medical College and Hindu Rao Hospital, Delhi.

Address for Correspondence
Nadeem Ahmad,
Assistant Professor,
Department of Microbiology,
University College of Medical Sciences and GTB Hospital,
Delhi
E-mail: nadeemahmad411@gmail.com.

Citation
Ahmad N, Jain S. A 4 Year Analysis of Seasonality and Trends of Tuberculosis from 2016 to 2019 at a Tertiary Care Center in North Delhi. Online J Health Allied Scs. 2021;20(2):7. Available at URL: https://www.ojhas.org/issue78/2021-2-7.html

Submitted: Apr 9, 2021; Accepted: Aug 6, 2021; Published: Aug 25, 2021

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This work is licensed under a Creative Commons Attribution-No Derivative Works 2.5 India License

Abstract: Purpose: Tuberculosis is a chronic infectious disease caused by Mycobacterium tuberculosis and transmitted by untreated smear-positive pulmonary tuberculosis cases while coughing, and sneezing. This retrospective study was aimed to assess the tuberculosis seasonality and trend analysis among patients attending various clinics of Hindu Rao Hospital between 2016-2019. Methods: Retrospective data analysis of samples sent to Mycobacteriology laboratory of Hindu Rao Hospital for ZN staining procedure for tuberculosis from patients attending various clinics of Hindu Rao Hospital during 2016-2019 was done. Results: In our study, during the course of 4 years, 263 (2.66%) out of total 9855 samples were positive for acid fast bacilli by ZN staining method. Out of 263 cases, 201 (76.42%) were pulmonary tuberculosis and 62 (23.57%) cases were of extrapulmonary tuberculosis. Conclusion: Like pulmonary tuberculosis, extrapulmonary tuberculosis is also a significant health problem in India and carries an important role in epidemiology of tuberculosis. Necessary and epidemiology based guided efforts should be made and directed towards early and prompt diagnosis of such cases with the help of more sensitive and specific newer diagnostic tests.
Key Words: Pulmonary tuberculosis, Extrapulmonary tuberculosis

Introduction:

Tuberculosis (TB) is an chronic infectious disease, caused mainly by Mycobacterium tuberculosis. It is highly transmitted by untreated smear-positive pulmonary tuberculosis cases when the infectious individual expels droplets of the bacilli which are produced while coughing, and sneezing.(1) The disease occurs due to the ability of the bacteria to overcome immune defences and multiplication, and as a result of all this the bacterial population become large enough in number to cause tissue damage. Any part of the body can be infected by Mycobacterium tuberculosis. It typically attacks the lungs as well as other parts of the body like lymph nodes, lung pleura, kidney etc.(2)

About one-third population in the world has dormant M. tuberculosis infection and hence is at risk of getting a full blown disease. This also has an effect on the socio-economic development of a country, as 75% of people with tuberculosis are within the economically productive age group of 15–54 years.(3) The risk of developing tuberculosis disease after infection with Mycobacterium tuberculosis depends upon various factors, the most important of which is a weakened immune system.(4)

The estimated TB incidence in India was 27 lakh in 2018. The RNTCP was able to achieve a notification of 21.5 Lakh in 2018, a increase of 16% as compared to previous year 2017. The epidemiological features of the affected population remain largely similar with majority of the affected individuals belonging to the age group of 15-69 years and about 2/3^rdof the population being males. HIV co-infection among TB was nearly fifty thousand cases amounting to TB HIV co-infection rate of 3.4%.(5)

Trend analysis and assessment of TB seasonality helps to allocate resources appropriately regarding clinical evaluation and research enrolment in high TB burdened areas. Therefore, this retrospective study was aimed to assess the seasonality and trend analysis of TB among patients attending various clinics of Hindu Rao Hospital.

Methods

A retrospective analysis on tuberculosis was conducted by using data records from January 1, 2016 to December 31, 2019, at Department of Microbiology, North DMC Medical College and associated Hindu Rao Hospital. Data of acid fast staining procedure from all the pulmonary as well as extrapulmonary samples over a period of 4 years was analyzed in this study.

Statistical analysis

All the statistical calculations were done using MEDCALC software version 14.12.0 (Med Calc Software bvba, MedCalc Ostend, Belgium).

Results:

Table 1 shows the total number of samples received for acid fast staining and the positivity rate in the respective column. As can be seen in the table that there is a gradual increase in positivity rate from 2016 towards 2019.

Table 1: Total number of samples received and positivity rate
Year	No. of samples received	No. of AFB Positive	Positivity Rate (%)
2016	2490	40	1.6
2017	2702	74	2.73
2018	2240	67	2.99
2019	2423	82	3.38
Total	9855	263	2.66

Table 2 shows the month-wise breakup of AFB positive samples during respective years.

It can be seen in the table that positivity rate (not shown in the table) is less during cooler months as compared to relatively warmer months.

Table 2: Month-wise breakup of positive cases in respective years
Month	2016	2017	2018	2019
January	3	4	5	1
February	0	3	0	3
March	7	10	5	9
April	7	5	2	12
May	9	2	12	12
June	0	4	8	4
July	1	5	6	5
August	3	16	3	7
September	3	9	11	7
October	1	10	5	3
November	5	2	6	12
December	1	4	4	7
Total	40	74	67	82

Table 3 shows age distribution of positive cases in males and females. The male:female ratio in this study is 1.43:1 with prevalence of tuberculosis more in males as compared to females. In the table it can also be seen that age group between 21-50 years of age is the most affected group.

Table 3: Age distribution of positive cases in males and females.
Age Group (in yrs)	Male	Female
0-10	08	03
11-20	17	11
21-30	29	23
31-40	38	31
41-50	23	21
51-60	30	06
61-70	06	12
>70	04	01
Total	155	108

Table 4 shows positive pulmonary and extrapulmonary cases between 2016-2019.

Out of 263 positive samples, 201 were pulmonary sputum smear positive (76.42%) and 62 were extrapulmonary samples (23.57%).

Table 4: Positive pulmonary and extrapulmonary cases between 2016-2019
Year	Pulmonary	Extra Pulmonary	Total
2016	35	5	40
2017	52	22	74
2018	50	17	67
2019	64	18	82
Total	201	62	263

Discussion:

In our study, during the course of 4 years, 263 (2.66%) out of total 9855 samples were positive for acid fast bacilli by ZN staining method. There was a gradual increase in positivity rate with 2019 being the year with highest positivity rate (3.38%). The overall positivity rate in our study was 2.66%. The increase in positivity rate over a course of time can be explained by increased awareness and easy access to tuberculosis diagnostic facilities. As a result of which more and more people were seeking diagnosis and henceforth treatment for tuberculosis. Our findings collaborate with findings of Fereshtah Farzianpour et al who reported an increase in positivity of pulmonary and extrapulmonary forms of tuberculosis over a period of time.(6)

In our study, it was seen that positivity rate is less during cooler months as compared to relatively warmer months. Our finding support the fact that there are higher transmissions rates in winter followed by the subsequent development of disease several months later. Similar observations were made by Auda Fares et al in their study.(7) Similar findings were seen in studies by Varun Kumar et al and Pankaj Narula et al who also reported increased number of cases during warmer months.(8,9)

In the present study, the male:female ratio is 1.43:1 with prevalence of tuberculosis more in males as compared to females. The increased cases in males may be due to smoking habit in males which in turn is the most important risk factor for COPD and associated with development of pulmonary tuberculosis. Our finding corroborates with findings by Smith et al. (10)

In this study, the age group between 21-50 years of age is the most affected group. Higher incidence of tuberculosis in this age group may be attributed to alcohol abuse and smoking. The progression of recent infection as well as reactivation of latent disease may also contribute to higher incidence in this age group. Our findings are supported by study done by Marcoa et al.(11)

In our study, out of 263 cases, 201 (76.42%) were of pulmonary tuberculosis and 62 (23.57%) cases were of extrapulmonary tuberculosis. Out of 62 cases of extrapulmonary tuberculosis, 29 were of tubercular lymphadenitis, 10 were of pleural tuberculosis, 8 were of renal tuberculosis, 6 of tubercular osteomyelitis, 4 were of tubercular meningitis,3 were of endometrial tuberculosis and 2 of intestinal tuberculosis. Extrapulmonary tuberculosis is a significant health problem around the globe because of difficulties in its diagnosis and in monitoring of treatment. Extra pulmonary tuberculosis is mostly under-reported and it’s burden is gradually increasing, especially among HIV-infected patients.(12,13) Similar findings were seen in studies done by S Rama Prakasha et al which shows that lymph node tuberculosis as the most common extrapulmonary tuberculosis.(14) A study done by Anita Velingker et al shows rate of extra pulmonary tuberculosis to be 30.9% with highest proportion being formed by TB of pleural cavity 39.43%.(15)

Acknowledgements

The authors acknowledge the support provided by the staff members of Mycobacteriology laboratory of Hindu Rao Hospital, Delhi in this study.

Conflict of Interest

There is no conflict of interest to declare.

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