Patient risk factors for adverse drug events in hospitalized patients. ADE Prevention Study Group.

BACKGROUND: Adverse drug events (ADEs) are common in hospitalized patients, but few empirical data are available regarding the strength of patient risk factors for ADEs. METHODS: We performed a nested case-control study within a cohort that included 4108 admissions to a stratified random sample of 11 medical and surgical units in 2 tertiary care hospitals during a 6-month period. Analyses were conducted on 2 levels: (1) using a limited set of variables available for all patients using computerized data available from 1 hospital and (2) using a larger set of variables for the case patients and matched controls from both hospitals. Case patients were patients with an ADE, and the matched control for each case patient was the patient on the same unit as the case patient with the most similar prevent length of stay. Main outcome measures were presence of an ADE, preventable ADE, or severe ADE. RESULTS: In the cohort analysis, electrolyte concentrates (odds ratio [OR], 1.7), diuretics (OR, 1.7), and medical admission (OR, 1.6) were independent correlates of ADEs. Independent correlates of preventable ADEs in the cohort analysis were low platelet count (OR, 4.5), antidepressants (OR, 3.3), antihypertensive agents (OR, 2.9), medical admission (OR, 2.2), and electrolyte concentrates (OR, 2.1). In the case-control analysis, exposure to psychoactive drugs (OR, 2.1) was an independent correlate of an ADE, and use of cardiovascular drugs (OR, 2.4) was independently correlated with severe ADEs. For preventable ADEs, no independent predictors were retained after multivariate analysis. CONCLUSIONS: Adverse drug events occurred more frequently in sicker patients who stayed in the hospital longer. However, after controlling for level of care and preevent length of stay, few risk factors emerged. These results suggest that, rather than targeting ADE-prone individuals, prevention strategies should focus on improving medication systems.

Preventable adverse drug events in hospitalized patients: a comparative study of intensive care and general care units.

OBJECTIVES: To compare the frequency and preventability of adverse drug events and potential adverse drug events in intensive care units (ICUs) and non-ICUs. To evaluate systems factors involving the individual caregivers, care unit teams, and patients involved in each adverse drug event by comparing ICUs with non-ICUs and medical ICUs with surgical ICUs. DESIGN: Prospective cohort study. Participants included all 4,031 adult admissions to a stratified, random sample of 11 medical and surgical units in two tertiary care hospitals over a 6-month period. Units included two medical and three surgical ICUs and four medical and two surgical general care units. SETTING: Two tertiary care hospitals: Eleven medical and surgical units, including two medical and three surgical ICUs. PATIENTS: Adult admissions (n = 4,031). INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Rate of preventable adverse drug events and potential adverse drug events, length of stay, charges, costs, and measures of the unit's environment. Incidents were detected by stimulated self-report by nurses and pharmacists and by daily review of all charts by nurse investigators. Incidents were subsequently classified by two independent reviewers as to whether they represented adverse drug events or potential adverse drug events and as to severity and preventability. Those individuals involved in the preventable adverse drug event and potential adverse drug event underwent detailed interviews by peer case-investigators. The rate of preventable adverse drug events and potential adverse drug events in ICUs was 19 events per 1000 patient days, nearly twice that rate of non-ICUs (p <.01). The medical ICU rate (25 events per 1000 patient days) was significantly (p <.05) higher than the surgical ICU rate (14 events per 1000 patient days). When adjusted for the number of drugs used in the previous 24 hrs or ordered since admission, there were no differences in rates between ICUs and non-ICUs. ICU acuity, length of stay, and severity of the adverse drug event were greater in ICUs than non-ICUs, but there were no differences between medical ICU and surgical ICU patients. Structured interviews indicated almost no differences between ICUs and non-ICUs for many characteristics of the patient, patient care team, systems, and individual caregivers. CONCLUSIONS: The rate of preventable and potential adverse drug events was twice as high in ICUs compared with non-ICUs. However, when adjusted for the number of drugs ordered, there was no greater likelihood for preventable adverse drug events and potential adverse drug events to occur in ICUs than in non-ICUs. Preventable adverse drug events and potential adverse drug events occurred in units that functioned normally and involved caregivers who were working under reasonably normal circumstances, not at the extremes of workload, stress, or a difficult environment.

The costs of adverse drug events in hospitalized patients. Adverse Drug Events Prevention Study Group.

OBJECTIVE: To assess the additional resource utilization associated with an adverse drug event (ADE). DESIGN: Nested case-control study within a prospective cohort study. PARTICIPANTS: The cohort included 4108 admissions to a stratified random sample of 11 medical and surgical units in 2 tertiary-care hospitals over a 6-month period. Cases were patients with an ADE, and the control for each case was the patient on the same unit as the case with the most similar pre-event length of stay. MAIN OUTCOME MEASURES: Postevent length of stay and total costs. METHODS: Incidents were detected by self-report stimulated by nurses and pharmacists and by daily chart review, and were classified as to whether they represented ADEs. Information on length of stay and charges was obtained from billing data, and costs were estimated by multiplying components of charges times hospital-specific ratios of costs to charges. RESULTS: During the study period, there were 247 ADEs among 207 admissions. After outliers and multiple episodes were excluded, there were 190 ADEs, of which 60 were preventable. In paired regression analyses adjusting for multiple factors, including severity, comorbidity, and case mix, the additional length of stay associated with an ADE was 2.2 days (P=.04), and the increase in cost associated with an ADE was $3244 (P=.04). For preventable ADEs, the increases were 4.6 days in length of stay (P=.03) and $5857 in total cost (P=.07). After adjusting for our sampling strategy, the estimated postevent costs attributable to an ADE were $2595 for all ADEs and $4685 for preventable ADEs. Based on these costs and data about the incidence of ADEs, we estimate that the annual costs attributable to all ADEs and preventable ADEs for a 700-bed teaching hospital are $5.6 million and $2.8 million, respectively. CONCLUSIONS: The substantial costs of ADEs to hospitals justify investment in efforts to prevent these events. Moreover, these estimates are conservative because they do not include the costs of injuries to patients or malpractice costs.

Incidence of adverse drug events and potential adverse drug events. Implications for prevention. ADE Prevention Study Group.

OBJECTIVES: To assess incidence and preventability of adverse drug events (ADEs) and potential ADEs. To analyze preventable events to develop prevention strategies. DESIGN: Prospective cohort study. PARTICIPANTS: All 4031 adult admissions to a stratified random sample of 11 medical and surgical units in two tertiary care hospitals over a 6-month period. Units included two medical and three surgical intensive care units and four medical and two surgical general care units. MAIN OUTCOME MEASURES: Adverse drug events and potential ADEs. METHODS: Incidents were detected by stimulated self-report by nurses and pharmacists and by daily review of all charts by nurse investigators. Incidents were subsequently classified by two independent reviewers as to whether they represented ADEs or potential ADEs and as to severity and preventability. RESULTS: Over 6 months, 247 ADEs and 194 potential ADEs were identified. Extrapolated event rates were 6.5 ADEs and 5.5 potential ADEs per 100 nonobstetrical admissions, for mean numbers per hospital per year of approximately 1900 ADEs and 1600 potential ADEs. Of all ADEs, 1% were fatal (none preventable), 12% life-threatening, 30% serious, and 57% significant. Twenty-eight percent were judged preventable. Of the life-threatening and serious ADEs, 42% were preventable, compared with 18% of significant ADEs. Errors resulting in preventable ADEs occurred most often at the stages of ordering (56%) and administration (34%); transcription (6%) and dispensing errors (4%) were less common. Errors were much more likely to be intercepted if the error occurred earlier in the process: 48% at the ordering stage vs 0% at the administration stage. CONCLUSION: Adverse drug events were common and often preventable; serious ADEs were more likely to be preventable. Most resulted from errors at the ordering stage, but many also occurred at the administration stage. Prevention strategies should target both stages of the drug delivery process.

How well does a journal's peer review process function? A survey of authors' opinions.

OBJECTIVE: To evaluate the authors' satisfaction or dissatisfaction with the peer review process of the Journal of Clinical Anesthesia. DESIGN: Anonymous questionnaires were sent to authors to survey their opinions about specific aspects of the peer review process. Authors were grouped by status of their manuscripts: AR (accept with revision), RR (reject but may resubmit), and RO (reject outright). PARTICIPANTS: Authors of unsolicited manuscripts submitted in 1991 to 1992. MAIN OUTCOME MEASURES: Factors that determine authors' satisfaction with the relevancy and benefit of peer review of their manuscript. RESULTS: Significantly more authors of AR manuscripts responded to our survey than did authors of rejected manuscripts and viewed the review process more favorably. Authors of AR manuscripts were more satisfied with specific aspects of the review process, which led to improvement in their manuscripts. More authors of RR manuscripts believed that our review process improved subsequent manuscript preparation than did authors of accepted manuscripts. CONCLUSIONS: The surveying of authors, important clients of the peer review process, should guide change necessary to better serve our authors and improve peer review.

Diagnosis of a left-sided superior vena cava during placement of a pulmonary artery catheter.

We report a case of a left sided superior vena cava (SVC) that was diagnosed during placement of a pulmonary artery (PA) catheter. After entering the left internal jugular, the PA catheter passed into the left side of the heart, through the aortic valve, and into the aorta. This was an unusual cause of right-to-left shunting and persistent cyanosis in a patient who had undergone two open cardiac procedures, including repair of an atrial septal defect. Cardiac catheterization and echocardiography also failed to reveal the abnormality. The embryology and physiology of a left sided SVC is reviewed, including an historical perspective. A discussion of the variants of the syndrome is included, as is a review of aberrant placement of central venous catheters.