Incidence of adverse events and negligence in hospitalized patients. TOP
Results of the Harvard Medical Practice Study I.
Brennan TA, Leape LL, Laird NM, Hebert L, Localio AR, Lawthers AG, Newhouse JP, Weiler PC, Hiatt HH. Division of General Medicine, Brigham and Women's Hospital, Boston, MA 02115.
N Engl J Med 1991 Feb 7;324(6):370-6
BACKGROUND. As part of an interdisciplinary study of medical injury and malpractice litigation, we estimated the incidence of adverse events, defined as injuries caused by medical management, and of the subgroup of such injuries that resulted from negligent or substandard care.
METHODS. We reviewed 30,121 randomly selected records from 51 randomly selected acute care, nonpsychiatric hospitals in New York State in 1984. We then developed population estimates of injuries and computed rates according to the age and sex of the patients as well as the specialties of the physicians.
RESULTS. Adverse events occurred in 3.7 percent of the hospitalizations (95 percent confidence interval, 3.2 to 4.2), and 27.6 percent of the adverse events were due to negligence (95 percent confidence interval, 22.5 to 32.6). Although 70.5 percent of the adverse events gave rise to disability lasting less than six months, 2.6 percent caused permanently disabling injuries and 13.6 percent led to death. The percentage of adverse events attributable to negligence increased in the categories of more severe injuries (Wald test chi 2 = 21.04, P less than 0.0001). Using weighted totals, we estimated that among the 2,671,863 patients discharged from New York hospitals in 1984 there were 98,609 adverse events and 27,179 adverse events involving negligence. Rates of adverse events rose with age (P less than 0.0001). The percentage of adverse events due to negligence was markedly higher among the elderly (P less than 0.01). There were significant differences in rates of adverse events among categories of clinical specialties (P less than 0.0001), but no differences in the percentage due to negligence.
CONCLUSIONS. There is a substantial amount of injury to patients from medical management, and many injuries are the result of substandard care. PMID: 1987460
The nature of adverse events in hospitalized patients. TOP
Results of the Harvard Medical Practice Study II.
Leape LL, Brennan TA, Laird N, Lawthers AG, Localio AR, Barnes BA, Hebert L, Newhouse JP, Weiler PC, Hiatt H.
Department of Health Policy and Management, Harvard School of Public Health, Boston, MA 02115.
N Engl J Med 1991 Feb 7;324(6):377-84
BACKGROUND. In a sample of 30,195 randomly selected hospital records, we identified 1133 patients (3.7 percent) with disabling injuries caused by medical treatment. We report here an analysis of these adverse events and their relation to error, negligence, and disability.
METHODS. Two physician-reviewers independently identified the adverse events and evaluated them with respect to negligence, errors in management, and extent of disability. One of the authors classified each event according to type of injury. We tested the significance of differences in rates of negligence and disability among categories with at least 30 adverse events.
RESULTS. Drug complications were the most common type of adverse event (19 percent), followed by wound infections (14 percent) and technical complications (13 percent). Nearly half the adverse events (48 percent) were associated with an operation. Adverse events during surgery were less likely to be caused by negligence (17 percent) than nonsurgical ones (37 percent). The proportion of adverse events due to negligence was highest for diagnostic mishaps (75 percent), noninvasive therapeutic mishaps ("errors of omission") (77 percent), and events occurring in the emergency room (70 percent). Errors in management were identified for 58 percent of the adverse events, among which nearly half were attributed to negligence.
CONCLUSIONS. Although the prevention of many adverse events must await improvements in medical knowledge, the high proportion that are due to management errors suggests that many others are potentially preventable now. Reducing the incidence of these events will require identifying their causes and developing methods to prevent error or reduce its effects.
PMID: 1824793
Relation between malpractice claims and adverse events due to negligence. TOP
Results of the Harvard Medical Practice Study III.
Localio AR, Lawthers AG, Brennan TA, Laird NM, Hebert LE, Peterson LM, Newhouse JP, Weiler PC, Hiatt HH.
Center for Biostatistics and Epidemiology, Penn State University College of Medicine, Hershey 17033.
N Engl J Med 1991 Jul 25;325(4):245-51
BACKGROUND AND METHODS. By matching the medical records of a random sample of 31,429 patients hospitalized in New York State in 1984 with statewide data on medical-malpractice claims, we identified patients who had filed claims against physicians and hospitals. These results were then compared with our findings, based on a review of the same medical records, regarding the incidence of injuries to patients caused by medical management (adverse events).
RESULTS. We identified 47 malpractice claims among 30,195 patients' records located on our initial visits to the hospitals, and 4 claims among 580 additional records located during follow-up visits. The overall rate of claims per discharge (weighted) was 0.13 percent (95 percent confidence interval, 0.076 to 0.18 percent). Of the 280 patients who had adverse events caused by medical negligence as defined by the study protocol, 8 filed malpractice claims (weighted rate, 1.53 percent; 95 percent confidence interval, 0 to 3.2 percent). By contrast, our estimate of the statewide ratio of adverse events caused by negligence (27,179) to malpractice claims (3570) is 7.6 to 1. This relative frequency overstates the chances that a negligent adverse event will produce a claim, however, because most of the events for which claims were made in the sample did not meet our definition of adverse events due to negligence.
CONCLUSIONS. Medical-malpractice litigation infrequently compensates patients injured by medical negligence and rarely identifies, and holds providers accountable for, substandard care. PMID: 2057025
A study of medical injury and medical malpractice.
Hiatt HH, Barnes BA, Brennan TA, Laird NM, Lawthers AG, Leape LL, Localio AR, Newhouse JP, Peterson LM, Thorpe KE, et al. Harvard School of Public Health, Boston, MA 02115.
N Engl J Med 1989 Aug 17;321(7):480-4
Incidence and types of adverse events and negligent care in Utah and Colorado. TOP
Thomas EJ, Studdert DM, Burstin HR, Orav EJ, Zeena T, Williams EJ, Howard KM, Weiler PC, Brennan TA.
Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.
Med Care 2000 Mar;38(3):261-71
BACKGROUND: The ongoing debate on the incidence and types of iatrogenic injuries in American hospitals has been informed primarily by the Harvard Medical Practice Study, which analyzed hospitalizations in New York in 1984. The generalizability of these findings is unknown and has been questioned by other studies.
OBJECTIVE: We used methods similar to the Harvard Medical Practice Study to estimate the incidence and types of adverse events and negligent adverse events in Utah and Colorado in 1992.
DESIGN AND SUBJECTS: We selected a representative sample of hospitals from Utah and Colorado and then randomly sampled 15,000 nonpsychiatric 1992 discharges. Each record was screened by a trained nurse-reviewer for 1 of 18 criteria associated with adverse events. If > or =1 criteria were present, the record was reviewed by a trained physician to determine whether an adverse event or negligent adverse event occurred and to classify the type of adverse event.
MEASURES: The measures were adverse events and negligent adverse events.
RESULTS: Adverse events occurred in 2.9+/-0.2% (mean+/-SD) of hospitalizations in each state. In Utah, 32.6+/-4% of adverse events were due to negligence; in Colorado, 27.4+/-2.4%. Death occurred in 6.6+/-1.2% of adverse events and 8.8+/-2.5% of negligent adverse events. Operative adverse events comprised 44.9% of all adverse events; 16.9% were negligent, and 16.6% resulted in permanent disability. Adverse drug events were the leading cause of nonoperative adverse events (19.3% of all adverse events; 35.1% were negligent, and 9.7% caused permanent disability). Most adverse events were attributed to surgeons (46.1%, 22.3% negligent) and internists (23.2%, 44.9% negligent).
CONCLUSIONS: The incidence and types of adverse events in Utah and Colorado in 1992 were similar to those in New York State in 1984. Iatrogenic injury continues to be a significant public health problem. Improving systems of surgical care and drug delivery could substantially reduce the burden of iatrogenic injury. PMID: 10718351
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