Screening intervals for diabetic retinopathy and incidence of visual loss: a systematic review.

Screening for diabetic retinopathy can help to prevent this complication, but evidence regarding frequency of screening is uncertain. This paper systematically reviews the published literature on the relationship between screening intervals for diabetic retinopathy and the incidence of visual loss. The PubMed and EMBASE databases were searched until December 2012. Twenty five studies fulfilled the inclusion criteria, as these assessed the incidence/prevalence of sight-threatening diabetic retinopathy in relation to screening frequency. The included studies comprised 15 evaluations of real-world screening programmes, three studies modelling the natural history of diabetic retinopathy and seven cost-effectiveness studies. In evaluations of diabetic retinopathy screening programmes, the appropriate screening interval ranged from one to four years, in people with no retinopathy at baseline. Despite study heterogeneity, the overall tendency observed in these programmes was that 2-year screening intervals among people with no diabetic retinopathy at diagnosis were not associated with high incidence of sight-threatening diabetic retinopathy. The modelling studies (non-economic and economic) assessed a range of screening intervals (1-5 years). The aggregated evidence from both the natural history and cost-effectiveness models favors a screening interval >1 year, but ≤2 years. Such an interval would be appropriate, safe and cost-effective for people with no diabetic retinopathy at diagnosis, while screening intervals ≤1 year would be preferable for people with pre-existing diabetic retinopathy. A 2-year screening interval for people with no sight threatening diabetic retinopathy at diagnosis may be safely adopted. For patients with pre-existing diabetic retinopathy, a shorter interval ≤1 year is warranted.

Variation in organ quality between liver transplant centers.

A wide spectrum of quality exists among deceased donor organs available for liver transplantation. It is unknown whether some transplant centers systematically use more low quality organs, and what factors might influence these decisions. We used hierarchical regression to measure variation in donor risk index (DRI) in the United States by region, organ procurement organization (OPO) and transplant center. The sample included all adults who underwent deceased donor liver transplantation between January 12, 2005 and February 1, 2009 (n = 23,810). Despite adjusting for the geographic region and OPO, transplant centers' mean DRI ranged from 1.27 to 1.74, and could not be explained by differences in patient populations such as disease severity. Larger volume centers and those having competing centers within their OPO were more likely to use higher risk organs, particularly among recipients with lower model for end-stage liver disease (MELD) scores. Centers using higher risk organs had equivalent waiting list mortality rates, but tended to have higher post-transplant mortality (hazard ratio 1.10 per 0.1 increase in mean DRI). In conclusion, the quality of deceased donor organ patients receive is variable and depends in part on the characteristics of the transplant center they visit.

Barriers to following dietary recommendations in Type 2 diabetes.

AIMS: To evaluate barriers to following dietary recommendations in patients with Type 2 diabetes. METHODS: We conducted focus groups and surveys in urban and suburban VA and academic medical centres. For the written survey, a self-administered questionnaire was mailed to a random sample of 446 patients with diabetes. For the focus groups, six groups of patients with diabetes (three urban, three suburban) were conducted, with 6-12 participants in each group. The focus groups explored barriers across various types of diabetes self-management; we extracted all comments relevant to barriers that limited patients' ability to follow a recommended diet. RESULTS: The written survey measured the burden of diabetes therapies (on a seven-point rating scale). Moderate diet was seen as a greater burden than oral agents (median 1 vs. 0, P = 0.001), but less of a burden than insulin (median 1 vs. 4, P < 0.001). A strict diet aimed at weight loss was rated as being similarly burdensome to insulin (median 4 vs. 4, P = NS). Despite this, self-reported adherence was much higher for both pills and insulin than it was for a moderate diet. In the focus groups, the most commonly identified barrier was the cost (14/14 reviews), followed by small portion sizes (13/14 reviews), support and family issues (13/14 reviews), and quality of life and lifestyle issues (12/14 reviews). Patients in the urban site, who were predominantly African-American, noted greater difficulties communicating with their provider about diet and social circumstances, and also that the rigid schedule of a diabetes diet was problematic. CONCLUSIONS: Barriers to adherence to dietary therapies are numerous, but some, such as cost, and in the urban setting, communication with providers, are potentially remediable. Interventions aimed at improving patients' ability to modify their diet need to specifically address these areas. Furthermore, treatment guidelines need to consider patients' preferences and barriers when setting goals for treatment.

Projections of demand and capacity for colonoscopy related to increasing rates of colorectal cancer screening in the United States.

BACKGROUND: There is debate about the optimal colorectal cancer screening test, partly because of concerns about colonoscopy demand. AIM: To quantify the demand for colonoscopy with different screening tests, and to estimate the ability of the United States health care system to meet demand. METHODS: We used a previously published Markov model and the United States census data to estimate colonoscopy demand. We then used an endoscopic database to compare current rates of screening-related colonoscopy with those projected by the model, and to estimate the number of endoscopists needed to meet colonoscopy demand. RESULTS: Annual demand for colonoscopy ranges from 2.21 to 7.96 million. Based on current practice patterns, demand exceeds current supply regardless of screening strategy. We estimate that an increase of at least 1360 gastroenterologists would be necessary to meet demand for colonoscopic screening undergone once at age 65, while colonoscopy every 10 years could require 32 700 more gastroenterologists. A system using dedicated endoscopists could meet demand with fewer endoscopists. CONCLUSIONS: Colorectal cancer screening leads to demand for colonoscopy that outstrips supply. Systems to train dedicated screening endoscopists may be necessary in order to provide population-wide screening. The costs and feasibility of establishing this infrastructure should be studied further.

Avoiding pitfalls in chronic disease quality measurement: a case for the next generation of technical quality measures.

The true utility of quality measurement lies in its ability to inspire quality improvement, with resultant enhancements in the processes and outcomes of care. Because quality measurement is expensive, it is difficult to justify using measures that are not likely to lead to important improvements in health. Many current measures of chronic disease technical quality, however, have one or more pitfalls that prevent them from motivating quality improvement reactions. These pitfalls include that: (1) measured processes of care lack strong links to outcomes; (2) actionable processes of care are not measured; (3) measures do not target those at highest risk; (4) measures do not allow for patient exceptions; and (5) intermediate outcome measures are not severity adjusted. To exemplify recent advancements and current pitfalls in chronic disease quality measurement, we examine the evolution of quality measures for diabetes mellitus and discuss the limitations of many currently used diabetes mellitus care measures. We then propose more clinically meaningful "tightly linked" measures that examine clinical processes directly linked to outcomes, target populations with specific diagnoses or intermediate disease outcomes that contribute to risk for poor downstream health outcomes, and explicitly incorporate exceptions. We believe that using more tightly linked measures in quality assessment will identify important quality of care problems and is more likely to produce improved outcomes for those with chronic diseases.

Estimating hospital deaths due to medical errors: preventability is in the eye of the reviewer.

CONTEXT: Studies using physician implicit review have suggested that the number of deaths due to medical errors in US hospitals is extremely high. However, some have questioned the validity of these estimates. OBJECTIVE: To examine the reliability of reviewer ratings of medical error and the implications of a death described as "preventable by better care" in terms of the probability of immediate and short-term survival if care had been optimal. DESIGN: Retrospective implicit review of medical records from 1995-1996. SETTING AND PARTICIPANTS: Fourteen board-certified, trained internists used a previously tested structured implicit review instrument to conduct 383 reviews of 111 hospital deaths at 7 Department of Veterans Affairs medical centers, oversampling for markers previously found to be associated with high rates of preventable deaths. Patients considered terminally ill who received comfort care only were excluded. MAIN OUTCOME MEASURES: Reviewer estimates of whether deaths could have been prevented by optimal care (rated on a 5-point scale) and of the probability that patients would have lived to discharge or for 3 months or more if care had been optimal (rated from 0%-100%). RESULTS: Similar to previous studies, almost a quarter (22.7%) of active-care patient deaths were rated as at least possibly preventable by optimal care, with 6.0% rated as probably or definitely preventable. Interrater reliability for these ratings was also similar to previous studies (0.34 for 2 reviewers). The reviewers' estimates of the percentage of patients who would have left the hospital alive had optimal care been provided was 6.0% (95% confidence interval [CI], 3.4%-8.6%). However, after considering 3-month prognosis and adjusting for the variability and skewness of reviewers' ratings, clinicians estimated that only 0.5% (95% CI, 0.3%-0.7%) of patients who died would have lived 3 months or more in good cognitive health if care had been optimal, representing roughly 1 patient per 10 000 admissions to the study hospitals. CONCLUSIONS: Medical errors are a major concern regardless of patients' life expectancies, but our study suggests that previous interpretations of medical error statistics are probably misleading. Our data place the estimates of preventable deaths in context, pointing out the limitations of this means of identifying medical errors and assessing their potential implications for patient outcomes.

Where health and welfare meet: social deprivation among patients in the emergency department.

CONTEXT: As a safety net provider for many disadvantaged Americans, the emergency department (ED) may be an efficient site not only for providing acute medical care, but also for addressing serious social needs. OBJECTIVE: To characterize the social needs of ED patients, and to evaluate whether the most disadvantaged patients have connections with the health and welfare system outside the ED. DESIGN: Cross-sectional survey conducted over 24 hours in the fall of 1997. SETTING: Three EDs: an urban public teaching hospital, a suburban university hospital, and a semirural community hospital. PARTICIPANTS: Consecutive patients presenting for care, including those transported by ambulance. The survey response rate was 91% (N = 300; urban = 115, suburban = 102, rural = 83). MAIN OUTCOME MEASURE: Index of socioeconomic deprivation described by the US Census Bureau (based on food, housing, and utilities). RESULTS: Of all ED patients, 31% reported one or more serious social deprivations. For example, 13% of urban patients reported not having enough food to eat, and 9% of rural patients reported disconnection of their gas or electricity (US population averages both less than 3%). While 40% of all patients had no consistent health care outside the ED (< or = 1 visit/year), those with higher levels of social deprivation had the least contact with the health care system outside the ED (P < .01). Although those with higher levels of deprivation were more likely to receive public assistance, still almost one-quarter of patients with high-level social deprivation were not receiving public aid. CONCLUSION: Many ED patients suffer from fundamental social deprivations that threaten basic health. The most disadvantaged of these patients frequently lack contact with other medical care sites or public assistance networks. Community efforts to address serious social deprivation should include partnerships with the local ED.

Who bounces back? Physiologic and other predictors of intensive care unit readmission.

OBJECTIVE: To determine the influence of changes in acute physiology scores (APS) and other patient characteristics on predicting intensive care unit (ICU) readmission. DESIGN: Secondary analysis of a prospective cohort study. SETTING: Single large university medical intensive care unit. PATIENTS: A total of 4,684 consecutive admissions from January 1, 1994, to April 1, 1998, to the medical ICU. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The independent influence of patient characteristics, including daily APS, admission diagnosis, treatment status, and admission location, on ICU readmission was evaluated using logistic regression. After accounting for first ICU admission deaths, 3,310 patients were "at-risk" for ICU readmission and 317 were readmitted (9.6%). Hospital mortality was five times higher (43% vs. 8%; p < .0001), and length of stay was two times longer (16 +/- 16 vs. 32 +/- 28 days; p < .001) in readmitted patients. Mean discharge APS was significantly higher in the readmitted group compared with the not readmitted group (43 +/- 19 vs. 34 +/- 18; p > .01). Significant independent predictors of ICU readmission included discharge APS >40 (odds ratio [OR] 2.1; 95% confidence interval [CI] 1.6-2.7; p < .0001), admission to the ICU from a general medicine ward (Floor) (OR 1.9; 95% CI 1.4-2.6; p < .0001), and transfer to the ICU from other hospital (Transfer) (OR 1.7; 95% CI 1.3-2.3; p < .01). The overall model calibration and discrimination were (H-L chi2 = 3.8, df = 8; p = .85) and (receiver operating characteristic 0.67), respectively. CONCLUSIONS: Patients readmitted to medical ICUs have significantly higher hospital lengths of stay and mortality. ICU readmissions may be more common among patients who respond poorly to treatment as measured by increased severity of illness at first ICU discharge and failure of prior therapy at another hospital or on a general medicine unit. Tertiary care ICUs may have higher than expected readmission rates and mortalities, even when accounting for severity of illness, if they care for significant numbers of transferred patients.

Report of the health care delivery work group: behavioral research related to the establishment of a chronic disease model for diabetes care.

As one of four work groups for the November 1999 conference on Behavioral Science Research in Diabetes, sponsored by the National Institute on Diabetes and Digestive and Kidney Diseases, the health care delivery work group evaluated the status of research on quality of care, patient-provider interactions, and health care systems' innovations related to improved diabetes outcomes. In addition, we made recommendations for future research. In this article, which was developed and modified at the November conference by experts in health care delivery, diabetes and behavioral science, we summarize the literature on patient-provider interactions, diabetes care and self-management support among underserved and minority populations, and implementation of chronic care management systems for diabetes. We conclude that, although the quality of care provided to the vast majority of diabetic patients is problematic, this is principally not the fault of either individual patients or health care professionals. Rather, it is a systems issue emanating from the acute illness model of care, which still predominates. Examples of proactive population-based chronic care management programs incorporating behavioral principles are discussed. The article concludes by identifying barriers to the establishment of a chronic care model (e.g., lack of supportive policies, understanding of population-based management, and information systems) and priorities for future research in this area needed to overcome these barriers.

Which colon cancer screening test? A comparison of costs, effectiveness, and compliance.

PURPOSE: Recent media reports have advocated the use of colonoscopy for colorectal cancer screening. However, colonoscopy is expensive compared with other screening modalities, such as fecal occult blood testing and flexible sigmoidoscopy. We sought to determine the cost effectiveness of different screening strategies for colorectal cancer at levels of compliance likely to be achieved in clinical practice. METHODS: A Markov decision model was used to examine screening strategies, including fecal occult blood testing alone, fecal occult blood testing combined with flexible sigmoidoscopy, flexible sigmoidoscopy alone, and colonoscopy. The timing and frequency of screening was varied to assess optimal screening intervals. Sensitivity analyses were conducted to assess the factors that have the greatest effect on the cost effectiveness of screening. RESULTS: All strategies are cost effective versus no screening, at less than $20,000 per life-year saved. Direct comparison suggests that the most effective strategies are twice-lifetime colonoscopy and flexible sigmoidoscopy combined with fecal occult blood testing. Assuming perfect compliance, flexible sigmoidoscopy combined with fecal occult blood testing is slightly more effective than twice-lifetime colonoscopy (at ages 50 and 60 years) but is substantially more expensive, with an incremental cost effectiveness of $390,000 per additional life-year saved. However, compliance with primary screening tests and colonoscopic follow-up for polyps affect screening decisions. Colonoscopy at ages 50 and 60 years is the preferred test regardless of compliance with the primary screening test. However, if follow-up colonoscopy for polyps is less than 75%, then even once-lifetime colonoscopy is preferred over most combinations of flexible sigmoidoscopy and fecal occult blood testing. Costs of colonoscopy and proportion of cancer arising from polyps also affect cost effectiveness. CONCLUSIONS: Colonoscopic screening for colorectal cancer appears preferable to current screening recommendations. Screening recommendations should be tailored to the compliance levels achievable in different practice settings.

Automated computerized intensive care unit severity of illness measure in the Department of Veterans Affairs: preliminary results. SISVistA Investigators. Scrutiny of ICU Severity Veterans Health Sysyems Technology Architecture.

OBJECTIVE: To evaluate the feasibility of an automated intensive care unit (ICU) risk adjustment tool (acronym: SISVistA) developed by selecting a subset of predictor variables from the Acute Physiology and Chronic Health Evaluation (APACHE) III available in the existing computerized database of the Department of Veterans Affairs (VA) healthcare system and modifying the APACHE diagnostic and comorbidity approach. DESIGN: Retrospective cohort study. SETTING: Six ICUs in three Ohio Veterans Affairs hospitals. PATIENT SELECTION: The first ICU admission of all patients from February 1996 through July 1997. OUTCOME MEASURE: Mortality at hospital discharge. METHODS: The predictor variables, including age, comorbidity, diagnosis, admission source (direct or transfer), and laboratory results (from the +/- 24-hr period surrounding admission), were extracted from computerized VA databases, and APACHE III weights were applied using customized software. The weights of all laboratory variables were added and treated as a single variable in the model. A logistic regression model was fitted to predict the outcome and the model was validated using a boot-strapping technique (1,000 repetitions). MAIN RESULTS: The analysis included all 4,651 eligible cases (442 deaths). The cohort was predominantly male (97.5%) and elderly (63.6 +/- 12.0 yrs). In multivariate analysis, significant predictors of hospital mortality included age (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.04-1.09), comorbidity (OR, 1.11; 95% CI, 1.08-1.15), total laboratory score (OR, 1.07; 95% CI, 1.06-1.08), direct ICU admission (OR, 0.39; 95% CI, 0.31-0.49), and several broad ICU diagnostic categories. The SISVistA model had excellent discrimination and calibration (C statistic = 0.86, goodness-of-fit statistics; p > .20). The area under the receiver operating characteristic curve of the validated model was 0.86. CONCLUSIONS: Using common data elements often found in hospital computer systems, SISVistA predicts hospital mortality among patients in Ohio VA ICUs. This preliminary study supports the development of an automated ICU risk prediction system on a more diverse population.

Estimating the microvascular benefits of screening for type 2 diabetes mellitus.

OBJECTIVE: To define the relative benefits of screening for diabetes and improved treatment programs and ways of improving the efficiency of screening for a population-based cohort derived from the Third National Health and Nutrition Examination Survey (NHANES III). METHODS: A Markov decision model is used to estimate microvascular benefits of glucose control for four different screening and treatment scenarios, including either universal screening or improved glucose control of known diabetic subjects, neither, or both. RESULTS: A population cohort of subjects with recent onset of diabetes (< 5 years) was derived from NHANES III (of whom close to half were unaware that they had diabetes). In this population-based cohort, the total benefit achievable by universal screening and improved treatment (limiting HbA1c to less than 9%) is a reduction of about 30,000 cases of blindness over the lifetime of the cohort. Screening alone results in 7% of this benefit, and improved treatment alone provides 65%. Screening a targeted group of patients with three or more risk factors for developing diabetes would reduce the number of required fasting glucose measurements needed by 82% and provide 50% of the total benefit of screening the entire population with a fasting glucose measurement. CONCLUSIONS: Morbidity from type 2 diabetes can be most effectively reduced by developing ways to modestly improve the glycemic control of known diabetic subjects, particularly those with high A1c's and early onset of disease. Targeting can significantly reduce the number of persons who need to be screened with a fasting blood test while preserving a large component of the benefit of screening.

Trends in domestic violence service and leadership: implications for an integrated shelter model.

Domestic violence is a dangerous and prevalent social problem affecting up to 4 million women and countless children annually. Shelters offer safety and an opportunity for change during the crisis of family violence. These individuals also have the potential for retraumatization if leadership within the program recapitulates the abuse and coercion felt at home. This article reviews three related trends through the lens of power and control--domestic violence policy and service, models of leadership, and the study of traumatic stress disorders and recovery--and describes their implications for modern shelter service delivery.

Department of Veterans Affairs' Quality Enhancement Research Initiative for Diabetes Mellitus.

Diabetes is a common disease, which frequently leads to serious, high-cost complications. Estimates show that in fiscal year 1994 (FY94), 12.5% of outpatients in the Veterans Health Administration (VHA) received diabetes-specific medications, accounted for almost 25% of all VHA pharmacy costs, had a hospitalization rate 1.6 times that of veterans without diabetes, and made 3.6 million outpatient visits to VA clinics. Research demonstrates that much of the mortality and morbidity associated with diabetes can be prevented, and rigorous evidence-based guidelines have been developed. The short-term objectives of the Quality Enhancement Research Initiative for Diabetes Mellitus (QUERI-DM) are to (1) gather baseline information on how current VHA diabetes care differs from the VHA guidelines, (2) develop an efficient, validated system for monitoring key diabetes quality standards in the VHA, (3) evaluate the effectiveness of current approaches to diabetes care and the success of guideline implementation initiatives, and (4) initiate 2 to 4 large-scale quality improvement projects to enhance adherence to practice guidelines and evaluate their impact on patient outcomes, including quality of life.

Are randomized controlled trials sufficient evidence to guide clinical practice in type II (non-insulin-dependent) diabetes mellitus?

Randomized controlled trials (RCTs) are often considered the standard for defining the practice of evidence-based medicine. Taken alone, they are, however, often insufficient to guide clinical care. Randomized controlled trials are clearly the best method to determine whether interventions are efficacious. They have, however, numerous limitations which make them difficult to carry out or limit applicability to routine clinical practice. Although observational studies also have inherent limitations, they provide data which can help to further explain the results of randomized controlled trials. The use of observational studies to frame randomized trials can allow better application of randomized controlled trial results to individual patients and can thus help to optimize delivery of care, inform clinical practice and determine the need for further such trials.

Cost-utility analysis of screening intervals for diabetic retinopathy in patients with type 2 diabetes mellitus.

CONTEXT: Annual eye screening for patients with diabetes mellitus is frequently proposed as a measure of quality of care. However, the benefit of annual vs less frequent screening intervals has not been well evaluated, especially for low-risk patients. OBJECTIVE: To examine the marginal cost-effectiveness of various screening intervals for eye disease in patients with type 2 diabetes, stratified by age and level of glycemic control. DESIGN: Markov cost-effectiveness model. SETTING AND PARTICIPANTS: Hypothetical patients based on the US population of diabetic patients older than 40 years from the Third National Health and Nutrition Examination Survey. MAIN OUTCOME MEASURES: Patient time spent blind, quality-adjusted life-years (QALYs), and costs of annual vs less frequent screening compared by age and level of hemoglobin A1c. RESULTS: Retinal screening in patients with type 2 diabetes is an effective intervention; however, the risk reduction varies dramatically by age and level of glycemic control. On average, a high-risk patient who is aged 45 years and has a hemoglobin A1c level of 11% gains 21 days of sight when screened annually as opposed to every third year, while a low-risk patient who is aged 65 years and has a hemoglobin A1c level of 7% gains an average of 3 days of sight. The marginal cost-effectiveness of screening annually vs every other year also varies; patients in the high-risk group cost an additional $40530 per QALY gained, while those in the low-risk group cost an additional $211570 per QALY gained. In the US population, retinal screening annually vs every other year for patients with type 2 diabetes costs $107510 per QALY gained, while screening every other year vs every third year costs $49760 per QALY gained. CONCLUSIONS: Annual retinal screening for all patients with type 2 diabetes without previously detected retinopathy may not be warranted on the basis of cost-effectiveness, and tailoring recommendations to individual circumstances may be preferable. Organizations evaluating quality of care should consider costs and benefits carefully before setting universal standards.

Discussion between reviewers does not improve reliability of peer review of hospital quality.

OBJECTIVES: Peer review is used to make final judgments about quality of care in many quality assurance activities. To overcome the low reliability of peer review, discussion between several reviewers is often recommended to point out overlooked information or allow for reconsideration of opinions and thus improve reliability. The authors assessed the impact of discussion between 2 reviewers on the reliability of peer review. METHODS: A group of 13 board-certified physicians completed a total of 741 structured implicit record reviews of 95 records for patients who experienced severe adverse events related to laboratory abnormalities while in the hospital (hypokalemia, hyperkalemia, renal failure, hyponatremia, and digoxin toxicity). They independently assessed the degree to which each adverse event was caused by medical care and the quality of the care leading up to the adverse event. Working in pairs, they then discussed differences of opinion, clarified factual discrepancies, and rerated the record. The authors compared the reliability of each measure before and after discussion, and between and within pairs of reviewers, using the intraclass correlation coefficient for continuous ratings and the kappa statistic for a dichotomized rating. RESULTS: The assessment of whether the laboratory abnormality was iatrogenic had a reliability of 0.46 before discussion and 0.71 after discussion between paired reviewers, indicating considerably improved agreement between the members of a pair. However, across reviewer pairs, the reviewer reliability was 0.36 before discussion and 0.40 after discussion. Similarly, for the rating of overall quality of care, reliability of physician review went from 0.35 before discussion to 0.58 after discussion as assessed by pair. However, across pairs the reliability increased only from 0.14 to 0.17. Even for prediscussion ratings, reliability was substantially higher between 2 members of a pair than across pairs, suggesting that reviewers who work in pairs learn to be more consistent with each other even before discussion, but this consistency also did not improve overall reliability across pairs. CONCLUSIONS: When 2 physicians discuss a record that they are reviewing, it substantially improves the agreement between those 2 physicians. However, this improvement is illusory, as discussion does not improve the overall reliability as assessed by examining the reliability between physicians who were part of different discussions. This finding may also have implications with regard to how disagreements are resolved on consensus panels, guideline committees, and reviews of literature quality for meta-analyses.

What is an error?

CONTEXT: Launched by the Institute of Medicine's report, "To Err is Human," the reduction of medical errors has become a top agenda item for virtually every part of the U.S. health care system. OBJECTIVE: To identify existing definitions of error, to determine the major issues in measuring errors, and to present recommendations for how best to proceed. DATA SOURCE: Medical literature on errors as well as the sociology and industrial psychology literature cited therein. RESULTS: We have four principal observations. First, errors have been defined in terms of failed processes without any link to subsequent harm. Second, only a few studies have actually measured errors, and these have not described the reliability of the measurement. Third, no studies directly examine the relationship between errors and adverse events. Fourth, the value of pursuing latent system errors (a concept pertaining to small, often trivial structure and process problems that interact in complex ways to produce catastrophe) using case studies or root cause analysis has not been demonstrated in either the medical or nonmedical literature. CONCLUSION: Medical error should be defined in terms of failed processes that are clearly linked to adverse outcomes. Efforts to reduce errors should be proportional to their impact on outcomes (preventable morbidity, mortality, and patient satisfaction) and the cost of preventing them. The error and the quality movements are analogous and require the same rigorous epidemiologic approach to establish which relationships are causal.