The effect of socioeconomic status on bone density testing in a public health-care system.

INTRODUCTION AND HYPOTHESIS: An inverse relationship exists between socio-economic status (SES) and osteoporotic fractures. In publicly funded health-care systems there should be no barriers to accessing bone mineral density (BMD) testing, especially for those at increased fracture risk. Our hypothesis was that there would be a positive association between SES and BMD utilization (i.e. higher utilization rates in higher income women), resulting in disparities that disadvantage lower SES or lower income women. METHODS: A population-based BMD database from the Manitoba Bone Density Program was utilized to assess the association between SES (defined using income quintiles) and BMD utilization rates in women aged 50 years and older (n=107,944) for the 2001-2002 fiscal year. Analyses were stratified by age (50-64 years old and 65 years or older) and by a morbidity index obtained from the Johns Hopkins University Adjusted Clinical Group Case-Mix Adjustment System. RESULTS: Regression models demonstrated significantly higher BMD utilization rates among high SES women in all age and morbidity strata. Rate ratios varied from 1.76 (95% CI: 1.52-2.04) in 50- to 64-year-old women to 2.36 (95% CI: 1.60-3.49) in low morbidity women aged 65 or older. CONCLUSION: Within the context of a publicly funded health-care system significant inverse associations are demonstrated between SES and BMD utilization rates. Further research is needed to better understand the nature of these associations and how they may contribute to health outcomes.

Performance of the ACG case-mix system in two Canadian provinces.

BACKGROUND: While the adjusted clinical group (ACG) system has been extensively validated in the United States, its use in other developed nations has been limited. This article examines the performance of the system in 2 Canadian provinces and assesses the extent to which ACGs can account for same-year and next-year health care expenditures. METHODS: The study population included all residents of Manitoba and British Columbia who were continuously enrolled in the provincial health plans from April 1, 1995, to March 31, 1997. ACGs were assigned through diagnoses from fee-for-service physician claims and hospital separation records. "Physician" costs were calculated from the fee-for-service tariffs, and for Manitobans, "total" costs were also computed by combining physician and hospital costs. Linear regression was used to examine the ability of the ACG system to explain variation in individual costs (truncated at the 99th percentile). RESULTS: The British Columbia and Manitoba data were generally acceptable, with fewer than 2% rejected diagnoses. Higher costs were associated with both the accumulation of morbidities and their relative severity. For physician costs, the ACG system explained approximately 50% and approximately 25% of the variation in same-year and next-year truncated costs, respectively. For total costs, the system explained approximately 40% and approximately 14% of these respective costs. CONCLUSIONS: The application of ACGs in Canada is feasible using existing data. The ability of the ACG system to explain variation in costs is similar to that found in US health systems. While application of ACGs in Canada shows promise, further research is required to examine how closely they reflect population morbidity burdens and health care needs.

Waiting times for surgical procedures.

OBJECTIVES: Polls show that nearly two thirds of Canadians believe that waiting times prior to surgery have increased in recent years. A study was undertaken in Manitoba to determine whether public perceptions about long and increasing waits were valid. RESEARCH DESIGN: Using administrative data, waiting times for 10 types of surgery-ranging from coronary artery bypass surgery and mastectomy to cataract surgery and hernia repairs-were studied over a 5-year period. RESULTS: Using each patient's preoperative visit to the surgeon as the beginning of the waiting time, median waiting times for most of the procedures studied were found to have, in fact, remained stable or fallen slightly over the period studied. CONCLUSIONS: Further, an examination of waiting times for cataract surgery demonstrated that allowing surgeons to practice in both public and private arenas seems to be counterproductive to providing good public service.

Issues in planning for specialist physicians.

OBJECTIVES: The Manitoba Centre for Health Policy and Evaluation worked in support of a provincial Physician Resource Committee to address questions pertinent to assessing Manitoba's supply of specialist physicians. RESEARCH DESIGN: Because there was no direct method of determining whether the province's supply of specialists was adequate, three types of evidence were reviewed: the supply of specialists relative to recommended population/physician ratios; the supply of specialists relative to other Canadian provinces; and the level of care delivered by specialists in Manitoba relative to other provinces. Four additional questions were addressed: is a problem developing from the aging of Manitoba's specialist physicians? and will the supply of specialists be sufficient to keep up with the aging of the population? How well do specialists serve as a provincial resource? and how well do specialists serve high-need populations?

Managing health services: how the Population Health Information System (POPULIS) works for policymakers.

OBJECTIVES: University-based researchers in Manitoba, Canada, have used administrative data routinely collected as part of the national health insurance plan to design an integrated database and population-based health information system. This information system is proving useful to policymakers for answering such questions as: Which populations need more physician services? Which need fewer? Are high-risk populations poorly served? or do they have poor health outcomes despite being well served? Does high utilization represent overuse? or is it related to high need? More specifically, this system provides decision makers with the capability to make critical comparisons across regions and subregions of residents' health status, socioeconomic risk characteristics and use of hospitals, nursing homes, and physicians. The system permits analyses of demographic changes, expenditure patterns, and hospital performance in relation to the population served. The integrated database has also facilitated outcomes research across hospitals and countries, utilization review within a single hospital, and longitudinal research on health reform. The discussion highlights the strengths of integrated population-based information in analyzing the health care system and raising important questions about the relationship between health care and health.

Assessing the extent of contamination in the Canadian National Breast Screening Study.

OBJECTIVE: To estimate the proportion of Canadian National Breast Screening Study (NBSS) participants who went outside the trial for a mammogram, based on health insurance claims data. METHOD: Prospective cohort study linking trial subjects with population-based administrative data. SUBJECTS: All NBSS participants enrolled in the Winnipeg screening center who had health insurance claims to Manitoba Health (n = 9,780). ANALYSIS: Claims for bilateral mammograms were compared by screening arm allocation and age group at enrollment. Mammograms likely to be "screening" were defined based on prior claim history. RESULTS: For women aged 40 to 49 at enrollment, 5.3% in the intervention group and 21.8% in the control group had a claim for at least one bilateral mammogram. After excluding nonscreening mammograms these proportions fell to 2.2% and 14.1% (P < 0.0001). For women aged 50 to 59, 4.5% in the intervention group and 16.7% of the control group had at least one claim for a bilateral mammogram. These proportions were 2.1% and 10.5% for screening (P < 0.0001). CONCLUSION: Health care utilization data can be used to estimate contamination in a screening trial. The levels of contamination resulting from participants going outside the study for a screening test can have an impact on the power of the study and need to be considered when interpreting results and planning future screening studies.

Alternative and complementary therapy use in pediatric oncology patients in British Columbia: prevalence and reasons for use and nonuse.

PURPOSE: Alternative and complementary therapies are infrequently studied in pediatric populations. We performed a population-based survey to aid health care workers in identifying and counseling parents who may use these remedies. PATIENTS AND METHODS: We retrospectively surveyed the parents of 583 pediatric patients diagnosed with cancer in British Columbia between 1989 and 1995. Prevalence and factors that influence the use and nonuse of alternative and complementary therapies were estimated. RESULTS: Alternative and complementary therapies were used by 42% of 366 respondents. Herbal teas, plant extracts, and therapeutic vitamins were the most commonly used alternative therapies. Relaxation/imagery strategies, massage, and therapeutic touch were the most commonly used complementary techniques. Factors that influenced the use of alternative/complementary therapies were prior use (chi2 = 60.0, P < .0001), prior positive attitude towards these remedies (chi2 = 41.6, P < .0001), soliciting information from family and friends (chi2 = 70.5, P < .0001) or from alternative care givers (chi2 = 58.7, P < .0001), high risk of death at diagnosis (chi2 = 9.6, P < .002), and advanced education of the father (chi2 = 7.4, P < .006) or mother (chi2 = 8.6, P < .003). Parents who used alternative/complementary therapies did so in conjunction with conventional medicine (98%). Lack of knowledge and fear of interference with conventional therapies were the most common reasons cited for nonuse. No parent believed that the quality of life of their child deteriorated due to the use of alternative/complementary therapies. CONCLUSION: Alternative and complementary therapy use in pediatric oncology patients is common. Factors have been identified that may be associated with undertaking their use.

Case-control study of primary human herpesvirus 6 infection in children with febrile seizures.

RATIONALE: Human herpesvirus 6 (HHV-6) has been demonstrated to be the causative agent in roseola infantum. It has been suggested that HHV-6 may have neurotropic properties and be involved in the pathogenesis of febrile seizures in infants. We describe a case-control study to examine the hypothesis that acute HHV-6 infection occurs more commonly in children with febrile seizures than in controls. METHODS: Patients presenting with a first or second febrile seizure between 6 months and 2 years of age were entered in the study. Control patients did not have a seizure but had similar inclusion and exclusion criteria. Specimens were obtained for HHV-6 viral serology and polymerase chain reaction in the acute stage and approximately 2 weeks later. A diagnosis of HHV-6 infection was based on HHV-6-specific IgM and IgG serology and HHV-6 polymerase chain reaction of peripheral blood mononuclear cells and saliva. RESULTS: Eighty-six patients (45 with febrile seizures; 41 controls) were enrolled. The HHV-6 infection status could be determined in only 68 patients (35 with febrile seizures; 33 controls). Acute HHV-6 infection was identified in 15 of 35 febrile seizure patients and in 15 of 33 controls. Evidence of past HHV-6 infection was demonstrated in 13 febrile seizure patients and in 8 controls. CONCLUSIONS: The incidence of primary HHV-6 infection is similar in patients with febrile seizures and age-matched controls. HHV-6 does not seem to be a major factor in the pathogenesis of first and second febrile seizures.

Managing health services: how administrative data and population-based analyses can focus the agenda.

University-based researchers in Manitoba, Canada, have used administrative data routinely collected as part of the national health insurance plan to design an integrated database and population-based health information system. This information system is proving useful to policymakers for providing answers to such questions as: which populations need more physician services? Which need fewer? Are high-risk populations poorly served or do they have poor health outcomes despite being well served? Does high utilization represent overuse or utilization related to high need? More specifically, this system provides decision-makers with the capability to make critical comparisons across regions and subregions of residents' health status, socioeconomic risk characteristics, and use of hospitals, nursing homes, and physicians. The system permits analyses of demographic changes, expenditure patterns, and hospital performance in relation to the population served. The integrated database has also facilitated outcomes research across hospitals and counties, utilization review within a single hospital, and longitudinal research on health reform. A particularly interesting application to planning physician supply and distribution is discussed. The discussion highlights the strengths of integrated population-based information in analyzing the health care system and raising important questions about the relationship between health care and health.

HLA-DR class II associations with rubella vaccine-induced joint manifestations.

HLA class II (HLA-DR) frequencies were examined in relation to incidence of acute arthralgia or arthritis in 283 white women who had received RA27/3 rubella vaccine (n = 146) or placebo (n = 137) postpartum. Leukocyte DNA was molecularly typed for HLA-DRB1 gene expression. Univariate analysis revealed higher frequencies of DR2 (odds ratio [OR], 4.8; 95% confidence interval [CI], 1.2-18.8) and DR5 (OR, 7.5; 95% CI, 1.5-37.5) but lower frequencies of DR4 (OR, 2.3; 95% CI, 1.1-4.9) and DR6 (OR, 2.8; 95% CI, 1.4-5.8), in rubella vaccinees compared with placebo recipients with arthropathy. Logistic regression modelling of DR, treatment, age, time postpartum, and arthropathy revealed that the odds of developing arthropathy was 1.9 times greater (95% CI, 1.07-3.44) after rubella vaccine than placebo. Risk for arthropathy (regardless of rubella vaccination) was also influenced by DR interactions: odds were 8 times greater in individuals with both DR1 and DR4 (95% CI, 1.45-44.02) and 7.1 times greater with both DR4 and DR6 present (95% CI, 1.85-27.52), suggesting that coexpression of these specificities may predispose to postpartum arthropathy.

The measurement of knee-heel length in newborn infants using a simple vernier calipers.

OBJECTIVE: To assess the usefulness of a simple vernier calipers for measuring knee-heel length in neonates. SUBJECTS AND METHODS: Using a simple vernier calipers, knee-heel length was measured five times by 2 observers in 50 babies (29M, 21F; mean birthweight 1597 g; median gestational age at birth 29 weeks) at a median postnatal age of 11 days. A subgroup of 20 babies had knee-heel length measured similarly at weekly intervals for 3 weeks. Corrected gestational age and weight were simultaneously recorded. One observer was experienced in using the vernier calipers. The precision of the calipers was established using 4 steel gauge blocks of varying length (7.62-10.17 cm). RESULTS: The calipers were very precise when measuring steel gauge blocks. In babies, there was a downward trend across the first 2 measurements for both observers, the measurements stabilizing over the last three. Using the final three measurements per baby (n = 50), the experienced observer had a mean standard deviation of 0.023 cm and mean coefficient of variation 0.23% when measuring an average knee-heel length of 9.99 cm. The inexperienced observer had a mean standard deviation of 0.057 cm and a mean coefficient of variation of 0.56%, when measuring an average knee-heel length of 10.14 cm. The inter-observer reliability, measured by the intra-class correlation coefficient, was 0.99. The agreement between observers was such that one observer measured knee-heel length consistently less (0.15 cm, SD 0.18 cm) than the other. The reliability for knee-heel length velocity was lower (R = 0.85), but agreement between observers was high with an average difference of 0.016 cm/week. Knee-heel length was significantly correlated (p < 0.001) with corrected gestational age (r = 0.85) and with weight (r = 0.96). There was a weaker but significant correlation (r = 0.47, p < 0.001) between knee-heel length velocity and rate of weight gain (g/day), indicating that weight gain may not always be accompanied by an increase in linear growth. CONCLUSION: The measurement of knee-heel length by a simple vernier calipers is an accurate, reproducible and non-invasive method of assessing short-term linear growth in neonates. However, it is recommended that measurements of knee-heel length in a individual baby should be made by a single experienced observer.

Randomised double-blind placebo-controlled study on adverse effects of rubella immunisation in seronegative women.

BACKGROUND: The objective of our study was to investigate the association of adverse clinical musculoskeletal and neurological events in healthy postpartum women with live attenuated (RA27/3 strain) rubella-virus vaccine, and to assess the frequency of acute and recurrent arthralgia and arthritis and associations with acute and recurrent muscle pain (myalgia) and neurological manifestations (paraesthesias). METHODS: We used a randomised placebo-controlled, double-blind design in a community setting. 636 women were enrolled and, after 90 women dropped out, 546 healthy women aged 18-41 years, who were rubella seronegative on routine screening were immunised parenterally with either monovalent live attenuated (RA27/3 strain) rubella vaccine (n = 270) or saline placebo (n = 276) in the postpartum period. Outcome measures were the occurrence of acute and persistent or recurrent joint manifestations (arthralgia or arthritis) at 1, 3, 6, 9, and 12 months after immunisation. Occurrence of muscle pain (myalgia), and neurological symptoms (paraesthesia) was also assessed at the same times. FINDINGS: 543 women completed 1-month follow-up. 456 women completed the 12-month assessment. There were no differences at the time of immunisation between rubella vaccine and placebo groups in distribution of age, ethnic origin, parity, time between delivery and immunisation, breastfeeding history, or histories of earlier rubella vaccination or joint complaints. Results indicated a significantly higher incidence (p = 0.006; odds ratio = 1.73 [95% CI = 1.17-2.57]) of acute joint manifestations in rubella-vaccine recipients (30%) than in placebo recipients (20%). Frequency of chronic (recurrent) arthralgia or arthritis was only marginally significant (p = 0.042; 1.58 [1.01-2.45]). INTERPRETATION: RA27/3 rubella vaccine given to seronegative women during the postpartum period was significantly associated with development of acute arthralgia or arthritis. Although the numbers of women assessed and length of follow-up revealed only marginally significant differences in persistent or recurrent joint manifestations between rubella vaccine and placebo recipients, it is possible that susceptible women who are given rubella vaccination may experience this outcome.

Prospective, open-label, add-on study of lamotrigine in 56 children with intractable generalized epilepsy.

The role of lamotrigine (LTG) in childhood epilepsy is emerging. We evaluated the efficacy and adverse effects of LTG in an open, prospective study of 56 children with generalized epilepsies. Six (11%) children became seizure-free, and 24 (43%) had greater than 50% reduction in seizure frequency. LTG was effective against a broad range of generalized seizure types. Three of 15 patients with Lennox-Gastaut syndrome achieved complete seizure control and eight demonstrated 50 to 99% improvement in seizure control. Increase in seizures (7) and rash (5) were the most common side effects. After valproate was discontinued, LTG therapy was resumed, with no recurrence of rash in any patient. This study suggests that LTG may be a useful drug in the treatment of generalized epilepsies in children.

Determinants of vaginal-perineal integrity and pelvic floor functioning in childbirth.

OBJECTIVES: Our purpose was to evaluate risk factors for severe vaginal-perineal trauma and to ascertain determinants of pelvic floor strength. STUDY DESIGN: Secondary analysis of 459 nulliparous women enrolled in a randomized controlled trial of episiotomy was carried out. In a multivariate analysis we examined the association between (1) sulcus tears, (2) third- or fourth-degree tears, and (3) pelvic floor strength and selected demographic, physiologic, pregnancy-related, and intrapartum factors. RESULTS: Unemployment and shorter second stage of labor were significant predictors of sulcus tears. Episiotomy, forceps use, and birth weight were important predictors of third- and fourth-degree tears. Whereas perineal intactness (use of episiotomy and spontaneous tears) was not influenced by exercise, a strong exercise profile was associated with fewer third- and fourth-degree tears in the presence of episiotomy. Exercise did not influence the rate of sulcus tears. A total of 35% of the variability in postpartum pelvic floor strength was explained by antepartum strength; however, we were only able to identify 5% of the factors contributing to antepartum pelvic floor strength. CONCLUSIONS: Determinants of sulcus tears appear to be present before pregnancy; third- and fourth-degree tears are related to physician management. Exercise mitigates the potential for severe trauma induced by episiotomy.

Using an alternative data source to examine randomization in the Canadian National Breast Screening Study.

Criticisms of the Canadian National Breast Screening Study (NBSS) assert that reported findings (more deaths in women aged 40-49 allocated to mammography versus no mammography and no difference in mortality between women who had mammography and physical examination versus physical examination alone for those aged 50-59) may be due to more women with prior breast disease being allocated to the mammography arms of the study. The possibility that allocation was not random was examined for NBSS participants in Manitoba, Canada, using health insurance data that were external to and independent of the NBSS. The study design consisted of a retrospective observation study using health insurance (claims) data to construct health histories of breast disease prior to NBSS entry. Self-reported breast disease from the NBSS entry questionnaires was compared to breast disease histories on the basis of health insurance claims. The setting consisted of one NBSS screening center in Winnipeg, Canada. The patient population consisted of 9477 women with at least one health insurance claim in the 24 months prior to NBSS entry. We determined the proportions of women within each study arm who had claims for breast disease, breast disease investigation, or xeromammograms in the 24 months prior to NBSS entry, and compared the proportion of women's self-reports of breast disease or xeromammography with the presence/absence of a claim prior to NBSS entry for breast disease or xeromammography. No significant differences in the proportion of women with prior histories of benign breast disease, investigation, or xeromammograms (p > 0.05) were found across the study arms. Nine women in the mammography group versus one in the no mammography group had one prior health insurance claim for breast cancer, but eight of these women had no subsequent claims for breast cancer. There were no differences across the study arms in the proportion of women who reported a prior history of breast disease or a prior xeromammogram for whom an insurance claim was found. Using data external to the NBSS for Manitoba participants, the study found no definitive evidence to support a nonrandom allocation of women with prior breast disease to the mammography arms of the study. However, generalizability to the other NBSS centers cannot be assured.

Population health and health care use: an information system for policy makers.

University-based researchers in Manitoba, Canada, have used administrative data routinely collected as part of the national health insurance plan to design a population-based health information system (POPULIS). Decision-makers can use this system to make critical comparisons across regions of residents' health status, socioeconomic risk characteristics, and use of hospitals, nursing homes, and physicians. Policy makers have found this information system useful in providing answers to questions they are often asked: Which populations need more physician services? Which need fewer? Are high-risk populations poorly served or do they have poor health outcomes despite being well served? Does high utilization represent overuse or is it related to high need? Three commentaries follow.

Stability and trends over 3 years of data.

Because the health status of a population does not usually respond immediately to interventions, whether social or medical, the ability to analyze change over time is important. Therefore, patterns of change and stability in health status and health care use of Manitoba residents during a 3-year period from 1990 to 1992 were analyzed using the Population-based Health Information System. This article presents summary findings and discusses methodological and policy issues arising from the analyses. A small but significant decrease in premature mortality (the primary health status indicator) was observed in most regions of the province, but two remote, northern regions, those whose residents scored at high socioeconomic risk, remained distinguished for their poor health status. These "poor health" regions also had the highest contact rates with primary caregivers, raising questions about the role of the health care system in improving the health of the population. A persistent increase in surgery was observed in several regions, led by increases in outpatient surgery over and above increases in the elderly population and beyond substitution for inpatient procedures. This trend (not obvious before these analyses) is important as hospitals move to expand their outpatient facilities in response to restraints on inpatient care.

Measuring the health of the population.

A set of 102 population-based indicators was developed from multiple administrative data sources; these indicators were used to compare the health status of 1 million Manitoba residents across eight administrative regions for 1 year. Marked variations in health status were shown. Despite theoretically equal access to care in a universally insured system and high rates of utilization of hospital and physician services, residents of Manitoba's two northern, more remote regions scored most poorly--consistently and with statistical significance--across a variety of health status indicators. The strength of the various indicators was evaluated, and premature mortality emerged as the most useful "flagship" indicator for future analyses. Indicators that purport to be sensitive to how well a health care system is performing showed patterns similar to those derived from more classic measures (eg, mortality, low birth weight). Furthermore, the "system sensitive indicators" did not appear to be sufficiently independent of utilization biases.

Assessing physicians' compliance with guidelines for Papanicolaou testing.

In this study, population-based data were used to examine the appropriateness of Papanicolaou (Pap) testing from the perspective of the women being tested and their physicians. The approach used is unique in its assessment of overtesting and undertesting in the primary care setting. From the data base of the province of Manitoba's universal health insurance plan, 4-year health histories (1981 to 1984) were constructed for each woman from a random sample of the population of women who, in 1982, were between the ages of 25 to 64 years (n = 22,287). At the last visit to a general practitioner, gynecologist, or general surgeon in 1984 (termed the current visit), the authors determined whether a Pap test was given for each woman. Using decision rules from a Canadian task force report on cervical screening and previous health history, the authors evaluated the appropriateness of screening by determining whether a Pap test was given and was needed, or whether a women who had not received a Pap test required one. Overall, 55.7% of women were tested appropriately. Of the 5352 women who received a Pap test at the current visit, 62.8% were overtested. Of the 16,935 women not tested at the current visit, 38.5% required screening (i.e. were undertested). Characteristics of a physician's practice that were significantly related to compliance with the guidelines included having a high proportion of patients visiting for obstetric or gynecologic reasons. Variables that were associated with negative compliance were 1) being a gynecologist; and 2) having a high proportion of patients who lived in inner city or rural areas. Because physicians are paid a fee for every Pap smear taken and the guidelines were well disseminated, these results should be reasonably representative of fee-for-service practice in North America, where preventive care is not subject to user charges. This study supports previous findings that a passive approach to dissemination of guidelines is insufficient to effect practice.

The Canadian four-centre study of anaesthetic outcomes: II. Can outcomes be used to assess the quality of anaesthesia care?

Since anaesthesia, unlike medical or surgical specialties, does not constitute treatment, this study sought to determine if methods used to assess medical or surgical outcomes (that is the determination of adverse outcome) are applicable to anaesthesia. Anaesthetists collected information on patient, surgical and anaesthetic factors while data on recovery room and postoperative events were evaluated by research nurses. Data on 27,184 inpatients were collected and the analysis of outcomes determined for the intraoperative, post-anaesthetic care unit and postoperative time periods. Logistic regression was used to control for differences in patient populations across the four hospitals. In addition, a random selection of 115 major events was classified by a panel of anaesthetists into anaesthesia, surgical and patient-disease contributions. Across the three time periods, large variations in minor outcomes were found across the four hospitals; these variations ranged from two- to five-fold after case-mix adjustment (age, physical status, sex, emergency versus elective and length of anaesthesia). The rates of major events and deaths were similar across three hospitals; one hospital had a lower mortality rate (P less than 0.001) but had a higher rate of all major events (P less than 0.0001). Of major events assessed by physician panels, 18.3% had some anaesthetic involvement and no deaths were attributable partially or wholly to anaesthesia. Possible reasons to account for these variations in outcome include compliance in recording events, inadequate case-mix adjustment, differences in interpretation of the variables (despite guidelines) and institutional differences in monitoring, charting and observation protocols. The authors conclude that measuring quality of care in anaesthesia by comparing major outcomes is unsatisfactory since the contribution of anaesthesia to perioperative outcomes is uncertain and that variations may be explained by institutional differences which are beyond the control of the anaesthetist. It is suggested that minor adverse events, particularly those of concern to the patient, should be the next focus for quality improvement in anaesthesia.