David S. Zingmond

Factors Predicting Complication Rates Following Total Knee Replacement

BACKGROUND The purpose of this investigation was to expand on previous studies by more fully examining the role of a variety of patient and hospital characteristics in determining adverse outcomes following total knee replacement. METHODS With use of data from all hospital admissions in California from 1991 through 2001, multiple logistic regression was performed on the information regarding patients treated with total knee replacement. Rates of mortality and readmission due to infection and pulmonary embolism during the first ninety days after discharge were regressed against a variety of independent variables, including demographic factors (age, gender, race, ethnicity, and insurance type), burden of comorbid disease (Charlson comorbidity index), and provider variables (hospital size, teaching status, and surgical volume). A separate baseline probability analysis was then performed to compare the relative importance of all predictor variables. RESULTS The sample size for this analysis was 222,684. A total of 1176 deaths (rate, 0.53%), 1586 infections (0.71%), and 914 pulmonary emboli (0.41%) occurred within the first ninety days after discharge. The average age of the patients at the time of surgery was sixty-nine years. Sixty-two percent of the patients were women, and 32% had a Charlson comorbidity index of >0. The significant predictors for complications (p < 0.05) included age, gender, race/ethnicity, Charlson comorbidity index, insurance type, and hospital volume. A baseline probability analysis was performed with the base case considered to be a white woman who was over the age of sixty-five years, had a Charlson comorbidity index of 0, had Medicare insurance, and was treated at a high-volume, non-teaching hospital. For a patient with the baseline case characteristics, the probability of death was 31/10,000, the probability of infection was 59/10,000, and the probability of pulmonary embolism was 41/10,000 in the first ninety days after discharge. Altering the base case by assuming that care was received at a low-volume hospital increased the expected mortality rate by a factor of 26%. Increasing the Charlson comorbidity index to 1 increased the mortality rate by 170%, whereas decreasing the age to younger than sixty-five years lowered the mortality rate by 73%. Hospital volume, comorbidity, and age had similar effects on the expected rates of readmission due to infection and pulmonary embolism. CONCLUSIONS The effects of age and the Charlson comorbidity index on the baseline probability of adverse outcomes following total knee replacement were shown to be similar to or greater than the effect of hospital volume. This study elucidates and compares the relative importance of the effects of several different factors on outcome. This information is important when considering the conclusions and implications of this type of policy-relevant outcomes research.

Effect of Emergency Department Crowding on Outcomes of Admitted Patients

STUDY OBJECTIVE Emergency department (ED) crowding is a prevalent health delivery problem and may adversely affect the outcomes of patients requiring admission. We assess the association of ED crowding with subsequent outcomes in a general population of hospitalized patients. METHODS We performed a retrospective cohort analysis of patients admitted in 2007 through the EDs of nonfederal, acute care hospitals in California. The primary outcome was inpatient mortality. Secondary outcomes included hospital length of stay and costs. ED crowding was established by the proxy measure of ambulance diversion hours on the day of admission. To control for hospital-level confounders of ambulance diversion, we defined periods of high ED crowding as those days within the top quartile of diversion hours for a specific facility. Hierarchic regression models controlled for demographics, time variables, patient comorbidities, primary diagnosis, and hospital fixed effects. We used bootstrap sampling to estimate excess outcomes attributable to ED crowding. RESULTS We studied 995,379 ED visits resulting in admission to 187 hospitals. Patients who were admitted on days with high ED crowding experienced 5% greater odds of inpatient death (95% confidence interval [CI] 2% to 8%), 0.8% longer hospital length of stay (95% CI 0.5% to 1%), and 1% increased costs per admission (95% CI 0.7% to 2%). Excess outcomes attributable to periods of high ED crowding included 300 inpatient deaths (95% CI 200 to 500 inpatient deaths), 6,200 hospital days (95% CI 2,800 to 8,900 hospital days), and

Complication rates following open reduction and internal fixation of ankle fractures.

17 million (95% CI

Comparison of Reoperation Rates Following Ankle Arthrodesis and Total Ankle Arthroplasty

11 to

A comparison of clinical registry versus administrative claims data for reporting of 30-day surgical complications.

23 million) in costs. CONCLUSION Periods of high ED crowding were associated with increased inpatient mortality and modest increases in length of stay and costs for admitted patients.

Association between occurrence of a postoperative complication and readmission: implications for quality improvement and cost savings.

BACKGROUND Ankle fractures are among the most common injuries treated by orthopaedic surgeons. The purpose of the present investigation was to examine the risks of complications after open reduction and internal fixation of ankle fractures in a large population-based study. METHODS With use of Californias discharge database, we identified 57,183 patients who had undergone open reduction and internal fixation of a lateral malleolar, bimalleolar, or trimalleolar ankle fracture as inpatients in the years 1995 through 2005. Short-term complications were examined on the basis of the rates of readmission within ninety days after discharge. The intermediate-term rate of reoperation for ankle fusion or arthroplasty was also analyzed. Logistic regression and proportional hazard regression models were used to determine the strength of the relationships between the rates of complications and fracture type, patient demographics and comorbidities, and hospital characteristics. RESULTS The overall rate of short-term complications was low, including the rates of pulmonary embolism (0.34%), mortality (1.07%), wound infection (1.44%), amputation (0.16%), and revision open reduction and internal fixation (0.82%). The intermediate-term rates of reoperation were also low, with ankle fusion or ankle replacement being performed in 0.96% of the patients who were observed for five years. Open fractures, age, and medical comorbidities were significant predictors of short-term complications. The presence of complicated diabetes was a particularly strong predictor (odds ratio, 2.30; p < 0.001), as was peripheral vascular disease (odds ratio, 1.65; p < 0.001). The intermediate-term rate of reoperation for ankle fusion or replacement was higher in patients with trimalleolar fractures (hazard ratio, 2.07; p < 0.001) and open fractures (hazard ratio, 5.29; p < 0.001). Treatment at a low-volume hospital was not significantly associated with either the aggregate risk of short-term complications or the risk of intermediate-term reoperation. CONCLUSIONS By analyzing a large, diverse patient population, the present study clarifies the risks associated with open reduction and internal fixation of ankle fractures. Open injury, diabetes, and peripheral vascular disease were strong risk factors predicting a complicated short-term postoperative course. Fracture type was a strong predictor of reoperation for ankle fusion or replacement. Hospital volume did not play a significant role in the rates of short-term or intermediate-term complications.

Linking hospital discharge and death records—accuracy and sources of bias

BACKGROUND The role of ankle arthroplasty in the treatment of ankle arthritis is controversial. Ankle fusion is commonly performed, but there is ongoing concern about functional limitations and arthritis in the adjacent subtalar joint following ankle arthrodesis. The use of ankle arthroplasty as an alternative to ankle fusion is expanding, but reported results have been limited to those in case series. The purpose of this study was to compare the reoperation rates following ankle arthrodesis and ankle replacement on the basis of observational, population-based data from all inpatient admissions in California over a ten-year period. Our hypothesis was that patients treated with ankle replacement would have a lower risk of undergoing subtalar fusion but a higher overall risk of undergoing major revision surgery. METHODS We used Californias hospital discharge database to identify patients who had undergone ankle replacement or ankle arthrodesis as inpatients in the years 1995 through 2004. Short-term outcomes, including rates of major revision surgery, pulmonary embolism, amputation, and infection, were examined. Long-term outcomes that were analyzed included the rates of major revision surgery and subtalar joint fusion. Logistic and proportional hazard regression models were used to estimate the impact of the choice of ankle replacement or ankle fusion on the rates of adverse outcomes, with adjustment for patient factors including age and comorbidity. RESULTS A total of 4705 ankle fusions and 480 ankle replacements were performed during the ten-year study period. Patients who had undergone ankle replacement had an increased risk of device-related infection and of having a major revision procedure. The rates of major revision surgery after ankle replacement were 9% at one year and 23% at five years compared with 5% and 11% following ankle arthrodesis. Patients treated with ankle arthrodesis had a higher rate of subtalar fusion at five years postoperatively (2.8%) than did those treated with ankle replacement (0.7%). Regression analysis confirmed a significant increase in the risk of major revision surgery (hazard ratio, 1.93 [95% confidence interval, 1.50 to 2.49]; p < 0.001) but a decreased risk of subtalar fusion (hazard ratio, 0.28 [95% confidence interval, 0.09 to 0.87]; p = 0.03) in patients treated with ankle replacement compared with those treated with ankle fusion. CONCLUSIONS This study confirms that, compared with ankle fusion, ankle replacement is associated with a higher risk of complications but also potential advantages in terms of a decreased risk of the patient requiring subtalar joint fusion. Additional controlled trials are needed to clarify the appropriate indications for ankle arthrodesis and ankle replacement.

the Diverse Older Hiv-positive Population: A National Profile of Economic Circumstances, Social Support, and Quality of Life

Objectives:To compare the recording of 30-day postoperative complications between a national clinical registry and Medicare inpatient claims data and to determine whether the addition of outpatient claims data improves concordance with the clinical registry. Background:Policymakers are increasingly discussing use of postoperative complication rates for value-based purchasing. There is debate regarding the optimal data source for such measures. Methods:Patient records (2005–2008) from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) were linked to Medicare inpatient and outpatient claims data sets. We assessed the ability of (1) Medicare inpatient claims and (2) Medicare inpatient and outpatient claims to detect a core set of ACS-NSQIP 30-day postoperative complications: superficial surgical site infection (SSI), deep/organ-space SSI, any SSI (superficial and/or deep/organ-space), urinary tract infection, pneumonia, sepsis, deep venous thrombosis (DVT), pulmonary embolism, venous thromboembolism (DVT and/or pulmonary embolism), and myocardial infarction. Agreement of patient-level complications by ACS-NSQIP versus Medicare was assessed by &kgr; statistics. Results:A total of 117,752 patients from more than 200 hospitals were studied. The sensitivity of inpatient claims data for detecting ACS-NSQIP complications ranged from 0.27 to 0.78; the percentage of false-positives ranged from 48% to 84%. Addition of outpatient claims data improved sensitivity slightly but also greatly increased the percentage of false-positives. Agreement was routinely poor between clinical and claims data for patient-level complications. Conclusions:This analysis demonstrates important differences between ACS-NSQIP and Medicare claims data sets for measuring surgical complications. Poor accuracy potentially makes claims data suboptimal for evaluating surgical complications. These findings have meaningful implications for performance measures currently being considered.

Factors predicting complication rates after primary shoulder arthroplasty.

Objective:To estimate the effect of preventing postoperative complications on readmission rates and costs. Background:Policymakers are targeting readmission for quality improvement and cost savings. Little is known regarding mutable factors associated with postoperative readmissions. Methods:Patient records (2005–2008) from the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) were linked to Medicare inpatient claims. Risk factors, procedure, and 30-day postoperative complications were determined from ACS-NSQIP. The 30-day postoperative readmission and costs were determined from Medicare. Occurrence of a postoperative complication included surgical site infections and cardiac, pulmonary, neurologic, and renal complications. Multivariate regression models predicted the effect of reducing complication rates on risk-adjusted readmission rates and costs by procedure. Results:The 30-day postoperative readmission rate was 12.8%. Complication rates for readmitted and nonreadmitted patients were 53% and 16% (P < 0.001). Patients with a postoperative complication had higher predicted probability of readmission and cost of readmission than patients without a complication. For the 20 procedures accounting for the greatest number of readmissions, reducing ACS-NSQIP complication rates by a relative 5% could result in prevention of 2092 readmissions per year and a savings to Medicare of

Differences in symptom expression in older HIV-positive patients: The Veterans Aging Cohort 3 Site Study and HIV Cost and Service Utilization Study experience

31.0 million per year. Preventing all ACS-NSQIP complications for these procedures could result in prevention of 41,846 readmissions per year and a savings of