Nirav R. Shah, MD, MPH, is Senior Scholar at Stanford University’s School of Medicine. He is a distinguished healthcare leader with experience as an operator, scientist, innovator, and regulator. His expertise spans public health, public and private health insurance, and clinical operations across the continuum of care. At Stanford, Dr. Shah conducts research on improving healthcare quality and safety while lowering cost, driving adoption of digital technologies, and quantitatively evaluating the resulting value for US and international health care systems. Dr. Shah is Board-certified in Internal Medicine and is a graduate of Harvard College and Yale School of Medicine. He is an Advisor to the CDC Director, Senior Fellow of the Institute for Healthcare Improvement (IHI), independent director of STERIS plc [NASDAQ:STE], and trustee of the John A. Hartford Foundation. Previously, he served as Chief Operating Officer of Kaiser Permanente in Southern California, and as Commissioner of the New York State Department of Health.
Adjunct Professor, Medicine - Primary Care and Population Health
Boards, Advisory Committees, Professional Organizations
Member, Advisory Committee to the CDC Director (2021 - Present)
Chairman of the Board, Linux Foundation Public Health (2021 - 2022)
Independent Director, STERIS plc (2018 - Present)
Trustee, John A Hartford Foundation (2017 - Present)
AB, Harvard College
MD, MPH, Yale University
- Building a National Public Health System in the United States. The New England journal of medicine 2022
- Diagnostic Excellence and Patient Safety: Strategies and Opportunities. JAMA 2022
- What AI in Health Care Can Learn from the Long Road to Autonomous Vehicles New England Journal of Medicine Catalyst 2022; March
- Empowering clinical research in a decentralized world. NPJ digital medicine 2021; 4 (1): 102
- An Impact-Oriented Approach to Epidemiological Modeling. Journal of general internal medicine 2020
Health Care in 2030: Will Artificial Intelligence Replace Physicians?
Annals of internal medicine
View details for PubMedID 30802901
Build vs. Buy: What Should Health Systems Do?
New England Journal of Medicine.
; Care Redesign
Full stack solutions are coming to health careNEJM Catalyst
- Predictive Analytics to Determine Next Year’s Highest-Cost Patients New England Journal of Medicine. 2017 ; NEJM Catalyst
- Healthcare's missing quality measure: time Harvard Business Review. 2017 ; Harvard Business Review
- Health Care That Targets Unmet Social Needs New England Jounal of Medicine. 2016 ; NEJM Catalyst
Integrating Public and Population Health Into Medical Education Curricula: Opportunities and Challenges for Reform.
Academic medicine : journal of the Association of American Medical Colleges
ABSTRACT: In a review of U.S. medical education curricular guidance, from premedical studies through to continuing medical education, Maeshiro and colleagues found limited examples of public and population health topics. In this Commentary, the authors emphasize the importance of including public and population health in the curriculum, pointing to curricular reform efforts to integrate these topics into teaching of basic sciences and clinical studies. In addition, they consider the expectations placed on physicians to meet the needs of the population and argue that policies that support public health funding, infrastructure, and workers are also critical to improving the health of communities.
View details for DOI 10.1097/ACM.0000000000005469
View details for PubMedID 37801585
Continuous monitoring of eating and sleeping behaviors in the home environments of older adults: a case study demonstration.
Frontiers in public health
2023; 11: 1277714
Accurate observation of patient functioning is necessary for rigorous clinical research and for improving the quality of patient care. However, clinic or laboratory environments systematically differ from the contexts of everyday life. Further, assessments that are completed in a single institutional session may not be generalizable. Here, we describe a computer vision methodology that measures human functioning continuously in the environments where patients live, sleep, and eat.
View details for DOI 10.3389/fpubh.2023.1277714
View details for PubMedID 38283288
View details for PubMedCentralID PMC10811267
Development and Assessment of an Artificial Intelligence-Based Tool for Ptosis Measurement in Adult Myasthenia Gravis Patients Using Selfie Video Clips Recorded on Smartphones.
2023; 7 (1): 63-73
Introduction: Myasthenia gravis (MG) is a rare autoimmune disease characterized by muscle weakness and fatigue. Ptosis (eyelid drooping) occurs due to fatigue of the muscles for eyelid elevation and is one symptom widely used by patients and healthcare providers to track progression of the disease. Margin reflex distance 1 (MRD1) is an accepted clinical measure of ptosis and is typically assessed using a hand-held ruler. In this work, we develop an AI model that enables automated measurement of MRD1 in self-recorded video clips collected using patient smartphones.Methods: A 3-month prospective observational study collected a dataset of video clips from patients with MG. Study participants were asked to perform an eyelid fatigability exercise to elicit ptosis while filming "selfie" videos on their smartphones. These images were collected in nonclinical settings, with no in-person training. The dataset was annotated by non-clinicians for (1) eye landmarks to establish ground truth MRD1 and (2) the quality of the video frames. The ground truth MRD1 (in millimeters, mm) was calculated from eye landmark annotations in the video frames using a standard conversion factor, the horizontal visible iris diameter of the human eye. To develop the model, we trained a neural network for eye landmark detection consisting of a ResNet50 backbone plus two dense layers of 78 dimensions on publicly available datasets. Only the ResNet50 backbone was used, discarding the last two layers. The embeddings from the ResNet50 were used as features for a support vector regressor (SVR) using a linear kernel, for regression to MRD1, in mm. The SVR was trained on data collected remotely from MG patients in the prospective study, split into training and development folds. The model's performance for MRD1 estimation was evaluated on a separate test fold from the study dataset.Results: On the full test fold (N = 664 images), the correlation between the ground truth and predicted MRD1 values was strong (r = 0.732). The mean absolute error was 0.822 mm; the mean of differences was -0.256 mm; and 95% limits of agreement (LOA) were -0.214-1.768 mm. Model performance showed no improvement when test data were gated to exclude "poor" quality images.Conclusions: On data generated under highly challenging real-world conditions from a variety of different smartphone devices, the model predicts MRD1 with a strong correlation (r = 0.732) between ground truth and predicted MRD1.
View details for DOI 10.1159/000531224
View details for PubMedID 37545566
A Brief History of Exposure Notification During the COVID-19 Pandemic in the United States, 2020-2021.
Public health reports (Washington, D.C. : 1974)
The swift global spread of COVID-19 prompted public health authorities to explore digital technologies to aid in contact tracing for infection control. Exposure notification, a mobile device-based technology that notifies individuals of potential exposure to COVID-19 without requiring personally identifiable information, has been broadly favored because of its relative ease of use, scalability, and protection of personal privacy. Although several exposure notification protocols were developed, a partnership between Google and Apple led to the development of the most widely implemented exposure notification protocol in the world, including in the United States. In this article, we first describe the development of the Google Apple Exposure Notification (GAEN) protocol, noting the value of the discourse among software developers and public health authorities concerning the protocol's design and features. We track states' deployment of GAEN mobile applications (apps) and population-level adoption rates, finding the nationwide rollout of GAEN apps to be more fragmented than anticipated. We then discuss how the limited data collected from these apps make assessments of their effectiveness challenging. Finally, we consider the importance of the federal government playing a greater role in GAEN's early development, emphasize the power of public-private partnerships, and highlight the overriding importance of public messaging over technological details.
View details for DOI 10.1177/00333549221099533
View details for PubMedID 35674242
Scaling Supply to Meet Behavioral Health Demand in New York State Nursing Homes
New England Journal of Medicine Catalyst
2022; 3 (10)
View details for DOI 10.1056/CAT.22.0196
Personalized digital intervention for depression based on social rhythm principles adds significantly to outpatient treatment.
Frontiers in digital health
2022; 4: 870522
We conducted a 16-week randomized controlled trial in psychiatric outpatients with a lifetime diagnosis of a mood and/or anxiety disorder to measure the impact of a first-of-its-kind precision digital intervention software solution based on social rhythm regulation principles. The full intent-to-treat (ITT) sample consisted of 133 individuals, aged 18-65. An exploratory sub-sample of interest was those individuals who presented with moderately severe to severe depression at study entry (baseline PHQ-8 score ≥15; N=28). Cue is a novel digital intervention platform that capitalizes on the smartphone's ability to continuously monitor depression-relevant behavior patterns and use each patient's behavioral data to provide timely, personalized "micro-interventions," making this the first example of a precision digital intervention of which we are aware. Participants were randomly allocated to receive Cue plus care-as-usual or digital monitoring only plus care as usual. Within the full study and depressed-at-entry samples, we fit a mixed effects model to test for group differences in the slope of depressive symptoms over 16 weeks. To account for the non-linear trajectory with more flexibility, we also fit a mixed effects model considering week as a categorical variable and used the resulting estimates to test the group difference in PHQ change from baseline to 16 weeks. In the full sample, the group difference in the slope of PHQ-8 was negligible (Cohen's d=-0.10); however, the Cue group demonstrated significantly greater improvement from baseline to 16 weeks (p=0.040). In the depressed-at-entry sample, we found evidence for benefit of Cue. The group difference in the slope of PHQ-8 (Cohen's d=-0.72) indicated a meaningfully more rapid rate of improvement in the intervention group than in the control group. The Cue group also demonstrated significantly greater improvement in PHQ-8 from baseline to 16 weeks (p=0.009). We are encouraged by the size of the intervention effect in those who were acutely ill at baseline, and by the finding that across all participants, 80% of whom were receiving pharmacotherapy, we observed significant benefit of Cue at 16 weeks of treatment. These findings suggest that a social rhythm-focused digital intervention platform may represent a useful and accessible adjunct to antidepressant treatment (https://clinicaltrials.gov/ct2/show/NCT03152864?term=ellen+frank&draw=2&rank=3).
View details for DOI 10.3389/fdgth.2022.870522
View details for PubMedID 36120713
- Predicting Environmental Allergies from Real World Data Through a Mobile Study Platform. Journal of asthma and allergy 2021; 14: 259–64
Mothers of children with major congenital anomalies have increased health care utilization over a 20-year post-birth time horizon.
2021; 16 (12): e0260962
OBJECTIVE: This population-based, matched cohort study aimed to evaluate utilization of health care services by mothers of children with major congenital anomalies (MCAs), compared to mothers of children without MCAs over a 20-year post-birth time horizon in Denmark.METHODS: Our analytic sample included mothers who gave birth to an infant with a MCA (n = 23,927) and a cohort of mothers matched to them by maternal age, parity and infant's year of birth (n = 239,076). Primary outcomes were period prevalence and mothers' quantity of health care utilization (primary, inpatient, outpatient, surgical, and psychiatric services) stratified by their child's age (i.e., ages 0-6 = before school, ages 7-13 = pre-school + primary education, and ages 14-18 = secondary education or higher). The secondary outcome measure was length of hospital stays. Outcome measures were adjusted for maternal age at delivery, parity, marital status, income quartile, level of education in the year prior to the index birth, previous spontaneous abortions, maternal pregnancy complications, maternal diabetes, hypertension, alcohol-related diseases, and maternal smoking.RESULTS: In both cohorts the majority of mothers were between 26 and 35 years of age, married, and employed, and 47% were primiparous. Mothers of infants with anomalies had greater utilization of outpatient, inpatient, surgical, and psychiatric services, compared with mothers in the matched cohort. Inpatient service utilization was greater in the exposed cohort up to 13 years after a child's birth, with the highest risk in the first six years after birth [adjusted risk ratio, 1.13; 95% confidence interval (CI), 1.12-1.14], with a decrease over time. Regarding the quantity of health care utilization, the greatest difference between the two groups was in inpatient service utilization, with a 39% increased rate in the exposed cohort during the first six years after birth (adjusted rate ratio, 1.39; 95% CI, 1.37-1.42). During the first 6 years after birth, mothers of children with anomalies stayed a median of 6 days (interquartile range [IQR], 3-13) in hospital overall, while the comparison cohort stayed a median of 4 days (IQR, 2-7) in hospital overall. Rates of utilization of outpatient clinics (adjusted rate ratio, 1.36; 95% CI, 1.29-1.42), as well as inpatient (adjusted rate ratio, 1.77; 95% CI, 1.68-1.87), and surgical services (adjusted rate ratio, 1.33; 95% CI, 1.26-1.41) was higher in mothers of children with multiple-organ MCAs during 0 to 6 years after birth. Among mothers at the lowest income levels, utilization of psychiatric clinic services increased to 59% and when their child was 7 to 13 years of age (adjusted rate ratio, 1.59; 95% CI, 1.24-2.03).CONCLUSION: Mothers of infants with a major congenital anomaly had greater health care utilization across services. Health care utilization decreased over time or remained stable for outpatient, inpatient, and surgical care services, whereas psychiatric utilization increased for up to 13 years after an affected child's birth. Healthcare utilization was significantly elevated among mothers of children with multiple MCAs and among those at the lowest income levels.
View details for DOI 10.1371/journal.pone.0260962
View details for PubMedID 34879106
Achieving a Quintuple Aim for Telehealth in Pediatrics.
Pediatric clinics of North America
2020; 67 (4): 683–705
Pediatric practice increasingly involves providing care for children with medical complexity. Telehealth offers a strategy for providers and health care systems to improve care for these patients and their families. However, lack of awareness related to the unintended negative consequences of telehealth on vulnerable populations--coupled with failure to intentional design best practices for telehealth initiatives--implies that these novel technologies may worsen health disparities in the long run. This article reviews the positive and negative implications of telehealth. In addition, to achieve optimal implementation of telehealth, it discusses 10 considerations to promote optimal care of children using these technologies.
View details for DOI 10.1016/j.pcl.2020.04.015
View details for PubMedID 32650867
Impact of Social Needs Navigation on Utilization Among High Utilizers in a Large Integrated Health System: a Quasi-experimental Study.
Journal of general internal medicine
BACKGROUND: Programs addressing social determinants of health for high-utilizing patients are gaining interest among health systems as an avenue to promote health and decrease utilization.OBJECTIVE: To evaluate impacts of a social needs screening and navigation program for adult predicted high utilizers on total medical visit utilization.DESIGN: A prospective, quasi-experimental study using an intent-to-treat propensity-weighted difference-in-differences approach. Stratified analyses assessed intervention effects among three low-socioeconomic status sub-samples: patients in low-income areas, in low-education areas, and with Medicaid insurance.PARTICIPANTS: Predicted high utilizers-patients predicted to be in the highest 1% for total utilization in a large integrated health system.INTERVENTION: A telephonic social needs screening and navigation program.MAIN MEASURES: Primary difference-in-difference analyses compared total visit count utilization, including outpatient, emergency department (ED), and inpatient utilization, between the intervention and control groups at both in-network and out-of-network facilities. Prevalence of social needs among sample patients and their connection rates to social needs resources are also described.KEY RESULTS: The study included 34,225 patients (7107 intervention, 27,118 control). Most (53%) patients screened reported social needs, but only a minority (10%) of those with a need were able to connect with resources to address these needs. Primary analysis found total utilization visits decreased 2.2% (95% CI -4.5%, 0.1%; p=0.058) in the intervention group. Stratified analyses showed decreases in total utilization for all low-socioeconomic status subgroups receiving the intervention compared with controls: -7.0% (95% CI -11.9%, -1.9%; p=0.008) in the low-income area group, -11.5% (-17.6%, 5.0%; p<0.001) in the low-education area group, and -12.1% (-18.1%, -5.6%; p<0.001) in the Medicaid group.CONCLUSIONS: Social needs navigation programs for high-utilizing patients may have modest effects on utilization for the population overall. However, significant decreases in utilization were found among low-socioeconomic status patients more likely to experience social needs.
View details for DOI 10.1007/s11606-019-05123-2
View details for PubMedID 31228054
Segmentation of High-Cost Adults in an Integrated Healthcare System Based on Empirical Clustering of Acute and Chronic Conditions
JOURNAL OF GENERAL INTERNAL MEDICINE
2018; 33 (12): 2171–79
High-cost patients are a frequent focus of improvement projects based on primary care and other settings. Efforts to characterize high-cost, high-need patients are needed to inform care planning, but such efforts often rely on a priori assumptions, masking underlying complexities of a heterogenous population.To define recognizable subgroups of patients among high-cost adults based on clinical conditions, and describe their survival and future spending.Retrospective observational cohort study.Within a large integrated delivery system with 2.7 million adult members, we selected the top 1% of continuously enrolled adults with respect to total healthcare expenditures during 2010.We used latent class analysis to identify clusters of alike patients based on 53 hierarchical condition categories. Prognosis as measured by healthcare spending and survival was assessed through 2014 for the resulting classes of patients.Among 21,183 high-cost adults, seven clinically distinctive subgroups of patients emerged. Classes included end-stage renal disease (12% of high-cost population), cardiopulmonary conditions (17%), diabetes with multiple comorbidities (8%), acute illness superimposed on chronic conditions (11%), conditions requiring highly specialized care (14%), neurologic and catastrophic conditions (5%), and patients with few comorbidities (the largest class, 33%). Over 4 years of follow-up, 6566 (31%) patients died, and survival in the classes ranged from 43 to 88%. Spending regressed to the mean in all classes except the ESRD and diabetes with multiple comorbidities groups.Data-driven characterization of high-cost adults yielded clinically intuitive classes that were associated with survival and reflected markedly different healthcare needs. Relatively few high-cost patients remain persistently high cost over 4 years. Our results suggest that high-cost patients, while not a monolithic group, can be segmented into few subgroups. These subgroups may be the focus of future work to understand appropriateness of care and design interventions accordingly.
View details for PubMedID 30182326
View details for PubMedCentralID PMC6258619
- Putting the Health of Communities and Populations First JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION 2016; 316 (16): 1649-1650
Redesigning the Regulatory Framework for Ambulatory Care Services in New York
2014; 92 (4): 776-795
Policy Points: The landscape of ambulatory care services in the United States is rapidly changing on account of payment reform, primary care transformation, and the rise of convenient care options such as retail clinics. New York State has undertaken a redesign of regulatory policy for ambulatory care rooted in the Triple Aim (better health, higher-quality care, lower costs)-with a particular emphasis on continuity of care for patients. Key tenets of the regulatory approach include defining and tracking the taxonomy of ambulatory care services as well as ensuring that convenient care options do not erode continuity of care for patients.While hospitals remain important centers of gravity in the health system, services are increasingly being delivered through ambulatory care. This shift to ambulatory care is giving rise to new delivery structures, such as retail clinics and urgent care centers, as well as reinventing existing ambulatory care capacity, as seen with the patient-centered medical home model and the movement toward team-based care. To protect the public's interests, oversight of ambulatory care services must keep pace with these rapid changes. With this purpose, in January 2013 the New York Public Health and Health Planning Council undertook a redesign of the regulatory framework for the state's ambulatory care services. This article describes the principles undergirding the framework as well as the regulatory recommendations themselves.We explored and analyzed the regulation of ambulatory care services in New York in accordance with the available gray and peer-reviewed literature and legislative documents. The deliberations of the Public Health and Health Planning Council informed our review.The vision of high-performing ambulatory care should be rooted in the Triple Aim (better health, higher-quality care, lower costs), with a particular emphasis on continuity of care for patients. There is a pressing need to better define the taxonomy of ambulatory care services. From the state government's perspective, this clarification requires better reporting from new health care entities (eg, retail clinics), connections with regional and state health information technology hubs, and coordination among state agencies. A uniform nomenclature also would improve consumers' understanding of rights and responsibilities. Finally, the regulatory mechanisms employed-from mandatory reporting to licensure to regional planning to the certificate of need-should remain flexible and match the degree of consensus regarding the appropriate regulatory path.Few other states have embarked on a wide-ranging assessment of their regulation of ambulatory care services. By moving toward adopting the regulatory approach described here, New York aims to balance sound oversight with pluralism and innovation in health care delivery.
View details for DOI 10.1111/1468-0009.12092
View details for Web of Science ID 000346588500013
View details for PubMedID 25492604
View details for PubMedCentralID PMC4266176
- Liberating Data to Transform Health Care New York's Open Data Experience JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION 2014; 311 (24): 2481-2482
- Housing as Health Care - New York's Boundary-Crossing Experiment NEW ENGLAND JOURNAL OF MEDICINE 2013; 369 (25): 2374-2377
- Managing the Human Toll Caused by Seasonal Influenza New York State's Mandate to Vaccinate or Mask JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION 2013; 310 (17): 1797-1798
- Should Health Care Systems Become Insurers? JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION 2013; 310 (15): 1561-1562
- Managing Potential Conflicts of Interest in State Medicaid Pharmacy and Therapeutics Committees Seeking Harmony JAMA INTERNAL MEDICINE 2013; 173 (5): 344-344
Methodological Controversies from Comparative Effectiveness (CE) Studies Using Claims vs. Electronic Health Record (EHR) Data
WILEY-BLACKWELL. 2010: S16–S17
View details for Web of Science ID 000209826200038
Pinch and elbow extension restoration in people with tetraplegia: a systematic review of the literature.
journal of hand surgery
2009; 34 (4): 692-699
We conducted a systematic review of the literature to summarize the available data on reconstructive surgeries involving pinch reconstruction and elbow extension restoration in people with tetraplegia.English-language and French-language articles and abstracts published between 1966 and February 2007, identified through MEDLINE and EMBASE searches, bibliography review, and expert consultation, were reviewed for original reports of outcomes with pinch reconstruction and elbow extension restoration in tetraplegic patients after a spinal cord injury. Two reviewers independently extracted data on patient characteristics, surgical methods, and patient outcomes.Our search identified 765 articles, of which 37 met eligibility criteria (one article contained information on both elbow and pinch procedures). Results from 377 pinch reconstructions in 23 studies and 201 elbow extension restorations in 14 studies were summarized. The mean Medical Research Council score for elbow extension went from 0 to 3.3 after reconstruction. The overall mean postoperative strength measured after surgery for pinch reconstruction was 2 kg.More than 500 patients having these procedures experienced a clinically important improvement for both procedures-one restoring elbow extension, and the other, pinch strength. Upper-limb surgeries markedly improved the hand function of people with tetraplegia.Therapeutic IV.
View details for DOI 10.1016/j.jhsa.2008.12.002
View details for PubMedID 19345872
View details for PubMedCentralID PMC2794307
- Utility of different lipid measures to predict coronary heart disease JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION 2008; 299 (1): 35-36
- Biomarkers for prediction of cardiovascular events NEW ENGLAND JOURNAL OF MEDICINE 2007; 356 (14): 1473-1474
Bridging the inferential gap: The electronic health record and clinical evidence
2007; 26 (2): W181-W191
Most clinical decisions involve bridging the inferential gap: Clinicians are required to "fill in" where they lack knowledge or where no knowledge yet exists. In this context we consider how the inferential gap is a product, in part, of how knowledge is created, the limits to gaining access to such knowledge, and the variable ways in which knowledge is translated into decisions. We consider how electronic health records (EHRs) will help narrow this gap by accelerating the creation of evidence relevant to everyday practice needs and facilitating real-time use of knowledge in practice.
View details for DOI 10.1377/hlthaff.26.2.w181
View details for Web of Science ID 000244763500057
View details for PubMedID 17259202
View details for PubMedCentralID PMC2670472
- What is the best evidence for making clinical decisions? JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION 2000; 284 (24): 3127-3127
Randomized, controlled trials, observational studies, and the hierarchy of research designs.
NEW ENGLAND JOURNAL OF MEDICINE
2000; 342 (25): 1887-1892
In the hierarchy of research designs, the results of randomized, controlled trials are considered to be evidence of the highest grade, whereas observational studies are viewed as having less validity because they reportedly overestimate treatment effects. We used published meta-analyses to identify randomized clinical trials and observational studies that examined the same clinical topics. We then compared the results of the original reports according to the type of research design.A search of the Medline data base for articles published in five major medical journals from 1991 to 1995 identified meta-analyses of randomized, controlled trials and meta-analyses of either cohort or case-control studies that assessed the same intervention. For each of five topics, summary estimates and 95 percent confidence intervals were calculated on the basis of data from the individual randomized, controlled trials and the individual observational studies.For the five clinical topics and 99 reports evaluated, the average results of the observational studies were remarkably similar to those of the randomized, controlled trials. For example, analysis of 13 randomized, controlled trials of the effectiveness of bacille Calmette-Guérin vaccine in preventing active tuberculosis yielded a relative risk of 0.49 (95 percent confidence interval, 0.34 to 0.70) among vaccinated patients, as compared with an odds ratio of 0.50 (95 percent confidence interval, 0.39 to 0.65) from 10 case-control studies. In addition, the range of the point estimates for the effect of vaccination was wider for the randomized, controlled trials (0.20 to 1.56) than for the observational studies (0.17 to 0.84).The results of well-designed observational studies (with either a cohort or a case-control design) do not systematically overestimate the magnitude of the effects of treatment as compared with those in randomized, controlled trials on the same topic.
View details for Web of Science ID 000087704700007
View details for PubMedID 10861325
View details for PubMedCentralID PMC1557642