The importance of place of residence in patient satisfaction

OBJECTIVE

To determine the effect of patients' place of residence on their evaluations of care, and to explore related policy implications.

STUDY DESIGN

We used a conditional regression analysis of stratum matched case controls to examine whether place of residence of patients living in the Greater Toronto Area (GTA) or in Ontario outside of the GTA affects patient satisfaction with their experiences during hospitalization.

SETTING

One hundred and six acute care hospitals located in the province of Ontario, Canada.

PARTICIPANTS

A total of 101 683 Ontario residents hospitalized as inpatients between 1 October 2002 and 30 June 2004.

MAIN OUTCOME MEASURES

Patient satisfaction indicators publicly reported in Ontario comprising patient perceptions of consideration, responsiveness, communication, and overall impressions, scored on a continuous scale from 1 to 100.

RESULTS

Patients who lived outside Toronto were consistently more satisfied than patients who lived inside Toronto when both types of patients were hospitalized in Toronto (P < 0.0001). In contrast, patients who lived inside Toronto were usually and substantially more satisfied than patients who lived outside Toronto when they were hospitalized in facilities outside Toronto (P < 0.02). These findings were consistent after adjustment for several patient-level predictor variables: age, sex, self-assessed health status and number of hospital stays in the last 6 months.

CONCLUSION

Findings suggest that where patients live has a small but potentially important impact on how they rate their care. Residence may therefore be considered when designing public reporting systems and pay-for-performance programs. Further attention to patient-level factors may be important to accurate and useful public reporting of patient satisfaction.

Contact patterns as a risk factor for bovine tuberculosis infection in a free-living adult brushtail possum Trichosurus vulpecula population

The aim of this study was to identify risk factors for bovine tuberculosis (TB) in a free-roaming, capture-mark-recapture monitored possum Trichosurus vulpecula population in a 22-ha study site at Castlepoint, New Zealand from 1 April 1989 to 31 March 1994. A matched case-control design was used to evaluate the influence of sex, habitat and contact opportunities on TB risk. Cases comprised possums identified as TB-positive throughout the study period. Controls were selected from the group of possums that were captured and showed no clinical signs of TB throughout the study period. Measures derived from a social network analysis of possum capture locations such as degree, clustering coefficient (CC) and betweenness were used to represent potential contact opportunities among possums. Network analysis measures recorded for individual possums in the 12-month period before a diagnosis of TB were evaluated in a conditional logistic regression model. We found no evidence of an association between case status and the total number of possums with which there was potential contact (degree) (P=0.5). The odds of cases being exposed to unit increases in the number of TB-positive contacts was 2.50 (95% CI 1.24-5.05; P<0.01) times that of controls. This effect was conditional on the total number of potential contacts made, with a negative interaction with increasing degree. These findings indicate that potential contact with TB-positive possums increases the odds of disease whereas potential contact with large numbers of possums does not. This suggests that multiple contacts with TB-positive possum(s) are necessary for transmission of TB and this is more likely to occur in networks that are smaller. We challenge the hypothesis that contact with large numbers of individuals increases the probability of becoming TB infected and argue that individual contact behaviour is a determinant of the creation of TB foci within free-living possum populations.

Ertapenem versus piperacillin/tazobactam for diabetic foot infections (SIDESTEP): prospective, randomised, controlled, double-blinded, multicentre trial

BACKGROUND

Diabetic foot infections are a common and serious problem, yet few randomised trials of adequate quality have compared the efficacy of the various antibiotic regimens available for their treatment. Our aim was to assess the efficacy and safety of ertapenem versus piperacillin/tazobactam for foot infections.

METHODS

We did a randomised, double-blinded, multicentre trial in adults (n=586) with diabetes and a foot infection classified as moderate-to-severe and requiring intravenous antibiotics. We assigned patients intravenous ertapenem (1 g daily; n=295) or piperacillin/tazobactam (3.375 g every 6 h; n=291) given for a minimum of 5 days, after which oral amoxicillin/clavulanic acid (875/125 mg every 12 h) could be given for up to 23 days. Investigators retained the option to administer vancomycin to patients in either group to ensure adequate coverage for potentially antibiotic resistant Enterococcus spp and meticillin-resistant Staphylococcus aureus (MRSA). Our primary outcome was the proportion of patients with a favourable clinical response (cure or improvement) on the day that intravenous antibiotic was discontinued. Analyses were by an evaluable-patient only approach. This study is registered with , number NCT00229112.

FINDINGS

Of the 576 patients treated, 445 were available for assessment at the end of intravenous therapy. Both baseline characteristics and favourable clinical response rates were similar for the 226 who received ertapenem and the 219 who received piperacillin/tazobactam (94%vs 92%, respectively; between treatment difference 1.9%, 95% CI -2.9 to 6.9). Rates of favourable microbiological responses (eradication rates and clinical outcomes, by pathogen) and adverse events did not differ between groups.

INTERPRETATION

Clinical and microbiological outcomes for patients treated with ertapenem were equivalent to those for patients treated with piperacillin/tazobactam, suggesting that this once-daily antibiotic should be considered for parenteral therapy of diabetic foot infections, when deemed appropriate.

Computer-aided detection of pulmonary nodules: influence of nodule characteristics on detection performance

AIM

To evaluate prospectively the influence of pulmonary nodule characteristics on detection performances of a computer-aided diagnosis (CAD) tool and experienced chest radiologists using multislice CT (MSCT).

MATERIALS AND METHODS

MSCT scans of 20 consecutive patients were evaluated by a CAD system and two independent chest radiologists for presence of pulmonary nodules. Nodule size, position, margin, matrix characteristics, vascular and pleural attachments and reader confidence were recorded and data compared with an independent standard of reference. Statistical analysis for predictors influencing nodule detection or reader performance included chi-squared, retrograde stepwise conditional logistic regression with odds ratios and nodule detection proportion estimates (DPE), and ROC analysis.

RESULTS

For 135 nodules, detection rates for CAD and readers were 76.3, 52.6 and 52.6%, respectively; false-positive rates were 0.55, 0.25 and 0.15 per examination, respectively. In consensus with CAD the reader detection rate increased to 93.3%, and the false-positive rate dropped to 0.1/scan. DPEs for nodules < or = 5 mm were significantly higher for ICAD than for the readers (p < 0.05). Absence of vascular attachment was the only significant predictor of nodule detection by CAD (p = 0.0006-0.008). There were no predictors of nodule detection for reader consensus with CAD. In contrast, vascular attachment predicted nodule detection by the readers (p = 0.0001-0.003). Reader sensitivity was higher for nodules with vascular attachment than for unattached nodules (sensitivities 0.768 and 0.369; 95% confidence intervals = 0.651-0.861 and 0.253-0.498, respectively).

CONCLUSION

CAD increases nodule detection rates, decreases false-positive rates and compensates for deficient reader performance in detection of smallest lesions and of nodules without vascular attachment.

Two-stage methods for the analysis of pooled data

Epidemiologic studies of disease often produce inconclusive or contradictory results due to small sample sizes or regional variations in the disease incidence or the exposures. To clarify these issues, researchers occasionally pool and reanalyse original data from several large studies. In this paper we explore the use of a two-stage random-effects model for analysing pooled case-control studies and undertake a thorough examination of bias in the pooled estimator under various conditions. The two-stage model analyses each study using the model appropriate to the design with study-specific confounders, and combines the individual study-specific adjusted log-odds ratios using a linear mixed-effects model; it is computationally simple and can incorporate study-level covariates and random effects. Simulations indicate that when the individual studies are large, two-stage methods produce nearly unbiased exposure estimates and standard errors of the exposure estimates from a generalized linear mixed model. By contrast, joint fixed-effects logistic regression produces attenuated exposure estimates and underestimates the standard error when heterogeneity is present. While bias in the pooled regression coefficient increases with interstudy heterogeneity for both models, it is much smaller using the two-stage model. In pooled analyses, where covariates may not be uniformly defined and coded across studies, and occasionally not measured in all studies, a joint model is often not feasible. The two-stage method is shown to be a simple, valid and practical method for the analysis of pooled binary data. The results are applied to a study of reproductive history and cutaneous melanoma risk in women using data from ten large case-control studies.

Fluorescent lights, ultraviolet lamps, and risk of cutaneous melanoma

Exposure to solar radiation is increasingly being associated with a risk of cutaneous melanoma, and some risk has also been attributed to exposure to fluorescent lights. The risk of cutaneous melanoma associated with exposure to some sources of artificial ultraviolet radiation was examined in a case-control study in a Scottish population with fairly low exposure to natural ultraviolet radiation. The risk was not significantly or consistently raised for exposure to fluorescent lights at home or at work. The use of ultraviolet lamps and sunbeds, however, was associated with a significantly increased risk (relative risk = 2.9; 95% confidence interval 1.3 to 6.4), and the risk was significantly related to duration of use. The risk was particularly raised among people who have first used [corrected] ultraviolet beds or lamps more than [corrected] five years before presentation (relative risk = 9.1; 95% confidence intervals 2.0-40.6), in whom it was significantly related to cumulative hours of exposure. The risks associated with exposure to ultraviolet lamps and sunbeds remained significant after adjustment for other risk factors for melanoma.

Bladder cancer among workers in the textile industry: results of a Spanish case-control study

This paper presents results from a case-control study carried out in the county of Mataro, Spain. The study was designed to investigate the possible causes of an unusually high mortality rate from bladder cancer in Mataro county as compared to Spain as a whole, and this report focuses on occupational exposures. The study is based on 57 cases who were hospitalized for or died from bladder cancer between 1978 and 1981. Two controls per case were matched for sex, age, residence, and date of either hospitalization or death. Information was collected on smoking, coffee drinking, and occupation. Occupational histories were then evaluated and coded blind by a group of occupational health physicians. Analyses were carried out by means of conditional logistic regression. Among a group of common occupational sectors, an increased risk for past employment in the textile industry (OR = 2.2; p = .038) was found. Further analyses indicated that the risk is particularly elevated (OR = 4.41; 95% confidence limits; 1.15-16.84) for subjects who worked in dyeing or printing and who were most probably exposed to azo-dyes. Exposure in the textile industry may be responsible for 16% of the bladder cancers in the Mataro area. A list of dyes commonly used in the Mataro textile industries was compiled and cross-checked with lists of substances tested or evaluated for carcinogenesis.

Relation between phenotype and banal melanocytic naevi

In a study of risk factors for the development of melanocytic naevi in relation to the pathogenesis of malignant melanoma 197 white adults were examined by four dermatologists and naevus counts correlated with several other features. Highly significant associations were found between large numbers of banal acquired melanocytic naevi and the ability to tan easily without burning (skin types 3 and 4; relative risk 4.6), brown or hazel eyes (relative risk 3.5), green or grey eyes (relative risk 3.5) and brown or black hair (relative risk 3.7). No significant associations with numbers of naevi were shown for parity or use of oral contraceptives or other steroid hormones. This is the first study to find any relation between melanocytic naevi and phenotypic factors in a white population.

Extensions of analytic methods for nested and population-based incident case-control studies

Nested case-control studies are extracted from cohort data in order to ease the burden of analysis or to enable more complete and thorough collection of data. To parallel a life table analysis and obtain unbiased estimates of the relative hazard (incidence density ratio), controls for each case should be selected without replacement from all noncase members of the case's risk set. In population-based incident case-control studies (or incident density case-control studies) cases are obtained from a well defined population, with matched controls selected from members of the population who are disease free at the time a case is incident. This type of study may be viewed as a sample from a prospective population consisting of successive age or calendar year cohorts and, thus, as a type of nested or synthetic retrospective study. With both of these study types the relative hazard can be estimated. The link, through the estimability of the relative hazard, between these case-control designs and cohort studies enables extensions of case-control methodology when there are several disease categories (competing risks), e.g. different cancer histologies or multiple disease types, and when diseases may recur (multiple incident times), e.g. multiple benign breast disease episodes or multiple infections. The application of these methods are valid for those situations in which disease incidence follows a proportional hazards model and the relative hazard is estimable. For several special cases, tests for a null association, homogeneity and trends are derived.

Coarse fishing and risk of urothelial cancer

In a case-control study of 240 men with urothelial cancer diagnosed in 1984 and 240 matched control subjects smoking and coarse fishing were found to be significantly associated with the disease. Duration of exposure to the chrysoidine azo dyes used to stain maggot bait was the most important predictor of risk; 5% of our cases were attributable to exposure to this dye. Chrysoidine dyes are chemically similar to some putative mammalian carcinogens and a constituent of hair dyes.

Stratified trend and homogeneity analyses of proportions and life table data

Tests for linear trend and homogeneity among proportions and analogous time adjusted tests for life table data are programmed for stratified data. For proportions, the maximum likelihood estimator of the common logistic slope and its approximate standard error is given. This parameter is related to the relative risk for the factor under test. The model is a simpler and more relevant subcase of the general linear multiple logistic model. Tests of fit include a chi-square test of departure from trend for both types of data, and, for proportions, a test for the equality of slopes among groups of strata. The program is particularly useful for large prospective studies in epidemiology, but may also prove helpful for case-control studies, clinical trials, and combining animal studies. Several optional analyses are included. The program generalizes most aspects of a previously published program by Thomas, Breslow, and Gart (Trend and homogeneity analyses of proportions and life table data. Comp. Biomed. Res. 10, 373 (1977)). A FORTRAN card deck with documentation is available upon request.