Indian Journal of Community Medicine

LETTER TO EDITOR
Year
: 2014  |  Volume : 39  |  Issue : 4  |  Page : 251-

Control group and refusal rate critiques about hepatitis C virus infection in HIV positive cases


Ali Kabir 
 Department of Epidemiology, School of Public Health, Shahid Beheshti University of Medical Sciences; Center for Educational Research in Medical Sciences, Tehran University of Medical Sciences, Tehran, Iran

Correspondence Address:
Ali Kabir
Department of Epidemiology, School of Public Health, Shahid Beheshti University of Medical Sciences; Center for Educational Research in Medical Sciences, Tehran University of Medical Sciences, Tehran
Iran




How to cite this article:
Kabir A. Control group and refusal rate critiques about hepatitis C virus infection in HIV positive cases.Indian J Community Med 2014;39:251-251


How to cite this URL:
Kabir A. Control group and refusal rate critiques about hepatitis C virus infection in HIV positive cases. Indian J Community Med [serial online] 2014 [cited 2021 Feb 28 ];39:251-251
Available from: https://www.ijcm.org.in/text.asp?2014/39/4/251/143032


Full Text

Sir,

The paper published in this journal about prevalence and risk factors of hepatitis C virus (HCV) infection in human immunodeficiency 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 define 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 specifically 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 field 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.

References

1Davarpanah 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.
2Rothman KJ. Greenland S, Lash T. Modern Epidemiology. 3 rd ed. Philadelphia: Lippincott Williams & Wilkins; 2012.