251 Indian Journal of Community Medicine/Vol 39/Issue 4/October 2014Sir, The paper published in this journal about prevalence and risk factors of hepatitis C virus HCV infection in human
Trang 1251 Indian Journal of Community Medicine/Vol 39/Issue 4/October 2014
Sir,
The paper published in this journal about prevalence
and risk factors of hepatitis C virus (HCV) infection in
human immunodefi ciency virus HIV positive cases of a
center in Iran(1) has some minor critiques
Without a suitable control group, we cannot conclude
that even high frequency behaviors like imprisonment
(88.9%), injecting drug use (79.2%), or any other variable
can be considered as risk factor We should defi ne risk
factors in comparison with a basic population Maybe
in some populations, such behaviors (variables) are
more prevalent and these variables can be considered
as protective factor Percentages higher than 50% for
example, do not mean that this variable is a risk factor
Authors did not even compare the total frequency
of these demographics and risk factors with other
subgroups in their study and mentioned percentages
in both HCV positive and negative cases In addition,
comparison of HCV positive and negative cases is not
completely logical specifi cally when the number of two
groups is imbalanced with 200 HCV-negative cases in
comparison with only 26 HCV-positive ones according
to ELISA In addition, the nature of sampling shows
that the controls are not representative of the
HCV-negative cases because of nonprobability sampling and
high refusal rate However, the study base of
HCV-positive and HCV-negative cases is similar and this
similarity rationalizes selecting HCV-negative samples
as controls;(2) but, with considering above mentioned
issues
I know that research in HIV fi eld is most of the time along with considerable missing data due to nonresponse
or refusal to participate and even dropout However, high refusal rate may distort the results Authors are encouraged to discuss this issue or at least do sensitivity analysis
Ali Kabir 1,2
1 Department of Epidemiology, School of Public Health, Shahid Beheshti University of Medical Sciences, 2 Center for Educational Research in Medical Sciences, Tehran University of Medical
Sciences, Tehran, Iran E-mail: aikabir@yahoo.com
References
1 Davarpanah MA, Khademolhosseini F, Rajaeefard A, Tavassoli
A, Yazdanfar SK, Rezaianzadeh A Hepatitis C Virus Infection
in HIV Positive Attendees of Shiraz Behavioral Diseases Consultation Center in Southern Iran Indian J Community Med 2013;38:86-91.
2 Rothman KJ Greenland S, Lash T Modern Epidemiology 3 rd ed Philadelphia: Lippincott Williams & Wilkins; 2012.
Control Group and Refusal Rate Critiques about Hepatitis C Virus Infection in HIV Positive Cases
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Website:
www.ijcm.org.in
DOI:
10.4103/0970-0218.143032
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