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   Table of Contents      
Year : 2020  |  Volume : 152  |  Issue : 1  |  Page : 147-148

Authors' response

1 Translational Global Health Policy Research Cell, New Delhi, India
2 Multidisciplinary Research Unit/Model Rural Health Research Unit, New Delhi, India
3 ICMR-National Institute of Medical Statistics, New Delhi, India
4 Division of Reproductive Biology, Maternal Health & Child Health, New Delhi, India
5 Division of Non-Communicable Diseases, Indian Council of Medical Research, New Delhi, India
6 Division of Clinical Medicine, ICMR-National Institute of Cholera & Enteric Diseases, Kolkata, West Bengal, India
7 Informatics, Systems & Research Management Cell, Indian Council of Medical Research, New Delhi, India
8 Division of Epidemiology & Communicable Diseases, Indian Council of Medical Research, New Delhi, India
9 Department of Health Research, Ministry of Health & Family Welfare; Indian Council of Medical Research, New Delhi, India
10 ICMR-National AIDS Research Institute, Pune, Maharashtra, India

Date of Web Publication13-Aug-2020

Correspondence Address:
Samiran Panda
ICMR-National AIDS Research Institute, Pune, Maharashtra
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Source of Support: None, Conflict of Interest: None

Read associated with this article

DOI: 10.4103/0971-5916.292093

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How to cite this article:
Chatterjee P, Anand T, Singh KJ, Rasaily R, Singh R, Das S, Singh H, Praharaj I, Gangakhedkar RR, Bhargava B, Panda S. Authors' response. Indian J Med Res 2020;152:147-8

How to cite this URL:
Chatterjee P, Anand T, Singh KJ, Rasaily R, Singh R, Das S, Singh H, Praharaj I, Gangakhedkar RR, Bhargava B, Panda S. Authors' response. Indian J Med Res [serial online] 2020 [cited 2021 Jul 27];152:147-8. Available from:

We thank the authors for a close reading of our article[1]. Given the known biases in recruiting study participants for a case-control study, we decided to choose symptomatic HCWs who were tested for SARS-CoV-2 infection to maintain evenness in the way cases and controls were selected. We would like to posit that the reasons for which asymptomatic HCWs got tested were likely to be different from those of symptomatic HCWs. Hence, to maintain comparability between the cases and controls, we decided to include only symptomatic HCWs. We tried to adhere to the basic tenets of case-control investigations - the cases and controls should be comparable, except in that the case group experienced the outcome of interest. In addition, we would like to add that an analysis of one million tests conducted in India between January and April 2020 has shown that about 28 per cent of SARS-CoV-2-positive patients are asymptomatic[2].

The standard practice in developing logistic regression models begins with the selection of independent variables using multiple strategies - known or established theories, existing evidence, exploratory analyses or a combination of these and other strategies[3]. The purpose of the univariate analysis was to identify the variables that were more likely to be statistically and biologically associated with the outcome of interest. To construct a parsimonious model, we chose to include biologically plausible variables which met a cut-off value (P <0.1). This is clarified in the subsection titled 'multivariate analysis'. Further, we would like to emphasize that it is important to limit the number of independent variables to avoid a mathematically unstable model with limited generalizability beyond the current data[4]. In order for readers to appreciate the process, and to declare the associations observed through the univariate analyses, we chose to present both analyses.

While we acknowledge the lower response rate, this is a known shortcoming of telephone-based surveys. While in-person interviewing remains the method providing the highest yield in terms of response efficiency and representativeness, it was an untenable strategy given the realities of the ongoing pandemic and restrictions imposed on the movement of people by the nationwide lockdown. Also noteworthy is that, compared to online, mail, or self-reported data collection, telephone-based surveys provide better representativeness, more complete data and higher data yield[5],[6]. To improve the response rate, we employed different strategies such as training of interviewers and multiple call attempts at different times of the day. Further, our study received higher response rates than similar methodologies employed to cover HCWs in India (paediatricians: 57%)[7] and abroad (Germany: physicians, 56%[8]; France: physicians, 59%[9] and USA: internists, 64%[10]).

The study participants were asked to declare the side effects experienced by them in our investigation. As noted in the 'Results' section, a very small proportion of the participants self-reported adverse effects linked to HCQ intake, and the frequency of occurrence of side effects was not significantly different across the case and control groups[1].

   References Top

Chatterjee P, Anand T, Singh KJ, Rasaily R, Singh R, Das S, et al. Healthcare workers & SARS-CoV-2 infection in India: A case-control investigation in the time of COVID-19. Indian J Med Res 2020; 151 : 459-67.  Back to cited text no. 1
ICMR COVID Study Group, COVID Epidemiology & Data Management Team, COVID Laboratory Team, VRDLN Team. Laboratory surveillance for SARS-CoV-2 in India: Performance of testing & descriptive epidemiology of detected COVID-19, January 22 - April 30, 2020. Indian J Med Res 2020; 151 : 424-37.  Back to cited text no. 2
Stoltzfus JC. Logistic regression: A brief primer. Acad Emerg Med 2011; 18 : 1099-104.  Back to cited text no. 3
Hosmer DW, Lemeshow S. Logistic regression for matched case-control studies. In: Shewhart WA, Wilks SS, editors. Applied logistic regression. Hoboken (NJ): John Wiley & Sons, Inc.; 2005. p. 223-59.  Back to cited text no. 4
Szolnoki G, Hoffmann D. Online, face-to-face and telephone surveys - Comparing different sampling methods in wine consumer research. Wine Econ Policy 2013; 2 : 57-66.  Back to cited text no. 5
Patnaik S, Brunskill E, Thies W. Evaluating the accuracy of data collection on mobile phones: A study of forms, SMS, and voice. International Conference on Information and Communication Technologies and Development (ICTD2009); 2009 Apr 17-19; Doha, Qatar. p. 74-84.  Back to cited text no. 6
Zhang RL, Thacker N, Choudhury P, Pazol K, Orenstein WA, Omer SB, et al. Comparison of two survey methods based on response distribution of pediatricians regarding immunization for children in India: Mail versus telephone. Int J Trop Dis Health 2016; 16 : 1-10.  Back to cited text no. 7
Gahr M, Eller J, Connemann BJ, Schönfeldt-Lecuona C. Subjective reasons for non-reporting of adverse drug reactions in a sample of physicians in outpatient care. Pharmacopsychiatry 2016; 49 : 57-61.  Back to cited text no. 8
Peretti-Watel P, Bendiane MK, Pegliasco H, Lapiana JM, Favre R, Galinier A, et al. Doctors' opinions on euthanasia, end of life care, and doctor-patient communication: Telephone survey in France. BMJ 2003; 327 : 595-6.  Back to cited text no. 9
DuVal G, Clarridge B, Gensler G, Danis M. A national survey of U.S. internists' experiences with ethical dilemmas and ethics consultation. J Gen Intern Med 2004; 19 : 251-8.  Back to cited text no. 10


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