This is a good retrospective observational study of the effects of HCQ and HCQ+AZT in the treatment of COVID19-infected hospitalized patients but it will be very much premature to conclude these drugs' role in treatment based on short experience and the following questions and concerns:ġ. I like to ask my patients who have formed their own, often erroneous, medical opinions, "which is more complicated, a nuclear reactor or the physicists who designed it?" Most of us would not presume to offer advice on the design of nuclear reactors, but we sure like to opine on scientific issues surrounding, for example, Covid-19. False interpretations of scientific data are rampant these days, and the public suffers from this. Scientists and health care providers need to guard against the inevitable politicization of scientific data and investigations. Now we have another study that fails to meet basic scientific standards and a difficult path forward to overcome this failure. This occurred despite the fact that many cancer treatment trials carry a higher mortality than does Covid-19. al.Ī separate study involving remdesivir was stopped early by The National Institute of Allergy and Infectious Diseases without achieving statistical significance due to ethical issues revolving around using a placebo for Covid-19 patients (2). A good clinical study is needed here, not "multiple sensitivity analyses" as done by Rosenberg et. in the NEJM May 11 issue was more balanced and left open the possibility that hydroxychloroquine could have had a modest effect to bring the mortality rate of sicker patients down closer to the mortality rate of those less sick. At the very least the word "may" should be replaced with the word "is". The statement that "interpretation of these findings may be limited by the observational design" is a cop-out. It is unfortunate that the authors of neither study make this clear. On the contrary, neither study was robust enough to draw definitive conclusions as CNN proposes. Today CNN posted a headline entitled "Yet another study shows hydroxychloroquine doesn't work against Covid-19". Both studies were observational neither had a control group. However, in both studies the treated patients were significantly sicker at baseline than the untreated groups. This study in JAMA and another appearing in the issue of NEJM (1) both show no clear benefit in treating Covid-19 infected patients with hydroxychloroquine.
Retrospective cohort studies have existed for approximately as long as prospective cohort studies. For example, the term is used in medicine, describing a look back at a patient's medical history or lifestyle. A retrospective cohort study, also called a historic cohort study, (from Latin retr, "look back") generally means to take a look back at events that already have taken place.Practically, you just dig into data (~EHR).The outcome has already happened (by the time of study design)!.
(Kalogeropoulos, 2014) Andreas Kalogeropoulos (2014).It can be analyzed by a Retrospective Analysis Task.
It can require sound data on exposure status for both cases and noncases at a designated earlier timepoint.A Retrospective Cohort Study is a cohort study that is a retrospective study (where exposure and outcome have already occurred at the start of the study).