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How Do You Know Which Health Care Effectiveness Research You Can Trust? A Guide to Study Design for the Perplexed.

Soumerai SB, Starr D, Majumdar SR - Prev Chronic Dis (2015)

View Article: PubMed Central - PubMed

Affiliation: Harvard Medical School and Harvard Pilgrim Health Care Institute, 133 Brookline Ave, 6th Floor, Boston, MA 02215. Email: ssoumerai@hms.harvard.edu. Dr Soumerai is also co-chair of the Evaluative Sciences and Statistics Concentration of Harvard University's PhD Program in Health Policy.

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Medscape, LLC is accredited by the ACCME to provide continuing medical education for physicians... Medscape, LLC designates this Journal-based CME activity for a maximum of 1... Upon completion of this activity, participants will be able to: Define healthy user bias in health care research and means to reduce it Assess means to reduce selection bias in health care research Assess how to overcome confounding factors by indication in health care research Evaluate social desirability bias and history bias in health care research Another pattern in the evolution of science is that early studies of new treatments tend to show the most dramatic, positive health effects, and these effects diminish or disappear as more rigorous and larger studies are conducted... As these positive effects decrease, harmful side effects emerge... Sometimes researchers may publish overly definitive conclusions using unreliable study designs, reasoning that it is better to have unreliable data than no data at all and that the natural progression of science will eventually sort things out... We do not agree... For example, one of many weak cohort studies purported to show that flu vaccines reduce mortality in the elderly (Figure 2)... This study, which was widely reported in the news media and influenced policy, found significant differences in the rate of flu-related deaths and hospitalizations among the vaccinated elderly compared with that of their unvaccinated peers... One of the oldest and most accepted “truths” in the history of medication safety research is that benzodiazepines (popular medications such as Valium and Xanax that are prescribed for sleep and anxiety) may cause hip fractures among the elderly... This intervention took place during an explosion of research and news media reporting on treatments for acute myocardial infarction that could have influenced the prescribing behavior of physicians... These data demonstrate that inpatient mortality in the United States was declining before, during, and after the 100,000 Lives Campaign... The program itself probably had no effect on the trend, yet the widespread policy and media reports led to several European countries adopting this “successful” model of patient safety at considerable costs... Subsequently, several large RCTs demonstrated that many components of the 100,000 Lives Campaign were not particularly effective, especially when compared with the benefits reported in the IHI’s press releases.

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Healthy user bias, a type of selection bias, is demonstrated in a study of 3,415 patients with pneumonia (and at high risk for flu and its complications), where elderly flu vaccine recipients were already healthier than nonrecipients. Figure is based on data extracted from Eurich et al (13).CharacteristicVaccinated, %Not Vaccinated, %Physically independent9584Received pneumococcal vaccine689Former smoker4230Statin user3525
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Figure 1: Healthy user bias, a type of selection bias, is demonstrated in a study of 3,415 patients with pneumonia (and at high risk for flu and its complications), where elderly flu vaccine recipients were already healthier than nonrecipients. Figure is based on data extracted from Eurich et al (13).CharacteristicVaccinated, %Not Vaccinated, %Physically independent9584Received pneumococcal vaccine689Former smoker4230Statin user3525

Mentions: These cohort studies, however, did not account for healthy user bias. For example, a study of 3,415 people with pneumonia (and at high risk for flu and its complications) illustrated that elderly people who received a flu vaccine were more than 7 times as likely to also receive the pneumococcal vaccine as elderly people who did not receive a flu vaccine (Figure 1). They were also more likely to be physically independent, have quit smoking, and to be taking statins, a medication that improves survival of patients with heart disease, diabetes, and other conditions and prevents heart attacks and strokes among the elderly (13). In short, elderly people who got the flu vaccine already were healthier, more active, and received more treatment than those who did not and so had lower rates of flu-related hospitalization and death during the study period (14).


How Do You Know Which Health Care Effectiveness Research You Can Trust? A Guide to Study Design for the Perplexed.

Soumerai SB, Starr D, Majumdar SR - Prev Chronic Dis (2015)

Healthy user bias, a type of selection bias, is demonstrated in a study of 3,415 patients with pneumonia (and at high risk for flu and its complications), where elderly flu vaccine recipients were already healthier than nonrecipients. Figure is based on data extracted from Eurich et al (13).CharacteristicVaccinated, %Not Vaccinated, %Physically independent9584Received pneumococcal vaccine689Former smoker4230Statin user3525
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4492215&req=5

Figure 1: Healthy user bias, a type of selection bias, is demonstrated in a study of 3,415 patients with pneumonia (and at high risk for flu and its complications), where elderly flu vaccine recipients were already healthier than nonrecipients. Figure is based on data extracted from Eurich et al (13).CharacteristicVaccinated, %Not Vaccinated, %Physically independent9584Received pneumococcal vaccine689Former smoker4230Statin user3525
Mentions: These cohort studies, however, did not account for healthy user bias. For example, a study of 3,415 people with pneumonia (and at high risk for flu and its complications) illustrated that elderly people who received a flu vaccine were more than 7 times as likely to also receive the pneumococcal vaccine as elderly people who did not receive a flu vaccine (Figure 1). They were also more likely to be physically independent, have quit smoking, and to be taking statins, a medication that improves survival of patients with heart disease, diabetes, and other conditions and prevents heart attacks and strokes among the elderly (13). In short, elderly people who got the flu vaccine already were healthier, more active, and received more treatment than those who did not and so had lower rates of flu-related hospitalization and death during the study period (14).

View Article: PubMed Central - PubMed

Affiliation: Harvard Medical School and Harvard Pilgrim Health Care Institute, 133 Brookline Ave, 6th Floor, Boston, MA 02215. Email: ssoumerai@hms.harvard.edu. Dr Soumerai is also co-chair of the Evaluative Sciences and Statistics Concentration of Harvard University's PhD Program in Health Policy.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

Medscape, LLC is accredited by the ACCME to provide continuing medical education for physicians... Medscape, LLC designates this Journal-based CME activity for a maximum of 1... Upon completion of this activity, participants will be able to: Define healthy user bias in health care research and means to reduce it Assess means to reduce selection bias in health care research Assess how to overcome confounding factors by indication in health care research Evaluate social desirability bias and history bias in health care research Another pattern in the evolution of science is that early studies of new treatments tend to show the most dramatic, positive health effects, and these effects diminish or disappear as more rigorous and larger studies are conducted... As these positive effects decrease, harmful side effects emerge... Sometimes researchers may publish overly definitive conclusions using unreliable study designs, reasoning that it is better to have unreliable data than no data at all and that the natural progression of science will eventually sort things out... We do not agree... For example, one of many weak cohort studies purported to show that flu vaccines reduce mortality in the elderly (Figure 2)... This study, which was widely reported in the news media and influenced policy, found significant differences in the rate of flu-related deaths and hospitalizations among the vaccinated elderly compared with that of their unvaccinated peers... One of the oldest and most accepted “truths” in the history of medication safety research is that benzodiazepines (popular medications such as Valium and Xanax that are prescribed for sleep and anxiety) may cause hip fractures among the elderly... This intervention took place during an explosion of research and news media reporting on treatments for acute myocardial infarction that could have influenced the prescribing behavior of physicians... These data demonstrate that inpatient mortality in the United States was declining before, during, and after the 100,000 Lives Campaign... The program itself probably had no effect on the trend, yet the widespread policy and media reports led to several European countries adopting this “successful” model of patient safety at considerable costs... Subsequently, several large RCTs demonstrated that many components of the 100,000 Lives Campaign were not particularly effective, especially when compared with the benefits reported in the IHI’s press releases.

Show MeSH
Related in: MedlinePlus