BACKGROUND In ambulatory care settings, patients with limited English proficiency receive lower quality of care. hospital longer for 7 of 23 conditions (unstable coronary syndromes and chest pain, coronary artery bypass grafting, stroke, craniotomy procedures, diabetes mellitus, major intestinal and rectal procedures, and elective hip replacement), with LOS differences ranging from approximately 0.7 to 4.3 days. A meta-analysis using all admission data exhibited that LEP patients stayed 6% (approximately 0.5 days) longer overall than EP patients (95% confidence interval, 0.04 to 327-97-9 0.07). LEP patients were not at increased risk of in-hospital death (relative odds, 1.0; 95% confidence interval, 0.9 to 1 1.1). CONCLUSIONS Patients with limited English proficiency have longer hospital stays for some medical and surgical conditions. Limited English proficiency does not impact in-hospital mortality. The effect of communication barriers on outcomes of care in the inpatient setting requires further exploration, particularly for selected conditions in which length of stay is usually significantly continuous. that the additional variable would be considered an explanatory variable 327-97-9 if, upon addition to the model, it changed the estimate of relative LOS by 10% or more.21 In order to evaluate the regularity of our results, we used an alternative modeling strategy in which all confounding variables were collapsed into a single adjustment variable known as the propensity score.23 Meta-analysis Using Case CCNE2 Mix Groups Case mix groups are assigned to each record in the database based on diagnosis codes, complications, 327-97-9 and process codes.10,11 We grouped patients by CMG in order to include more documents than our initial analysis of medical and surgical conditions. As a result, instead of evaluating the effect of English proficiency only in selected medical and surgical conditions, we analyzed all admissions grouped into CMGs. We applied our risk-adjustment models to CMGs, treating each CMG as a separate study, to obtain impartial risk-adjusted estimates of the effect of English proficiency. We excluded CMGs with fewer than 200 patients, fewer than 10 patients per English proficiency group (LOS analysis), and fewer than 6 deaths per English proficiency group (in-hospital mortality analysis). Our meta-analysis used Bayesian random-effects models24 to determine summary estimates of the relative LOS and the odds ratio for in-hospital mortality at UHN during the study period. Our Bayesian random-effects model generated both an estimate for the overall mean of the group of CMG-specific estimates as well as shrunken estimates for individual CMGs. Case mix group-specific estimates are adjusted or shrunken toward the overall mean by amounts that are proportional to their variances. For unadjusted analyses, categorical variables were compared using a test. We used a single sample binomial test to determine whether the proportion of conditions (or CMGs) with significant differences favoring one group was greater than what would be expected by chance. Statistical analyses were performed using SPSS for Windows, Release 9.0.0 (SPSS Inc., Chicago, Ill), and WinBUGS, Version 1.2 (MRC Biostatistics Unit, Cambridge, UK).25 Research Ethics The research protocol was approved by 327-97-9 the UHN Research Ethics Table. RESULTS Our main analysis of 23 medical and surgical conditions included 59,547 records, representing 44,983 patients. LEP patients were older, more often female, and experienced lower imputed income values and higher comorbidity scores (Table 1). The Toronto Western hospital experienced a significantly larger proportion of LEP patients than the other hospitals in the study. The 10 languages most frequently spoken by inpatients are also reported. Table 1 Baseline Characteristics of the 327-97-9 Length of Stay Cohort (= 44,983) Table 2 shows the unadjusted imply LOS. Adjusted results are reported as the LOS of LEP patients relative to EP patients. Limited English-proficient patients stayed significantly longer than EP patients in 7 (30%) of the 23 medical and surgical conditions; 3 of 13 medical conditions (unstable coronary syndromes and chest pain, diabetes mellitus, and stroke), and 4 of 10 surgical conditions (coronary artery bypass grafting, craniotomy procedures, elective hip replacement, and major intestinal and rectal procedures). This result is usually significant (< .001); we would expect a maximum of only 2 conditions to have statistically significantly longer LOS for LEP patients by chance alone if there were no true effect for any of the conditions. Moreover, in none of the conditions examined did LEP patients have statistically significantly shorter adjusted LOS than EP patients. Table 2 Unadjusted and Adjusted Length of Stay by English Proficiency Status We predicted imply LOS (on the original level) for 2 common patients differing only by English proficiency status, using Duan's smearing estimator. Predicted numbers of days for the significant conditions (EP, LEP patients) are as follows: unstable coronary syndromes (3.9, 5.0), diabetes (6.4, 8.2), stroke (12.1, 15.7), coronary artery bypass grafting (8.4, 9.0), craniotomy procedures (6.8, 7.9), elective hip replacement.