Heather Watson

Economic Burden of Periprosthetic Joint Infection in the United States

This study characterizes the patient and clinical factors influencing the economic burden of periprosthetic joint infection (PJI) in the United States. The 2001-2009 Nationwide Inpatient Sample was used to identify total hip and knee arthroplasties using International Classification of Diseases, Ninth Revision, procedure codes. The relative incidence of PJI ranged between 2.0% and 2.4% of total hip arthroplasties and total knee arthroplasties and increased over time. The mean cost to treat hip PJIs was

Infection risk for primary and revision instrumented lumbar spine fusion in the Medicare population

5965 greater than the mean cost for knee PJIs. The annual cost of infected revisions to US hospitals increased from

Dairy consumption and CVD: a systematic review and meta-analysis.

320 million to

Use of electronic medical records (EMR) for oncology outcomes research: assessing the comparability of EMR information to patient registry and health claims data

566 million during the study period and was projected to exceed

Liposomal Bupivacaine: A Comparative Study of More Than 1000 Total Joint Arthroplasty Cases

1.62 billion by 2020. As the demand for joint arthroplasty is expected to increase substantially over the coming decade, so too will the economic burden of prosthetic infections.

Diesel Engine Exhaust and Lung Cancer Mortality: Time-Related Factors in Exposure and Risk

OBJECT This retrospective analysis of Medicare administrative data was performed to evaluate the risk of infection following instrumented lumbar fusion over a 10-year follow-up period in the Medicare population. Although infection can be a devastating complication, due to its rarity it is difficult to characterize infection risk except in large patient populations. METHODS Using ICD-9-CM and CPT4 procedure codes, the Medicare 5% analytical research files for inpatient, outpatient, and physician carrier claims were checked to identify patients who were treated between 1997 and 2009 with lumbar spine fusion in which cages or posterior instrumentation were used. Patients younger than 65 years old were excluded. Patients were followed continuously by using the matching denominator file until they withdrew from Medicare or died. The authors identified 15,069 patients with primary fusion procedures and 605 with revision of instrumented lumbar fusion. Infections were identified by the related ICD-9 codes (998.59 or 996.67) after fusion. Kaplan-Meier survival analysis and Cox regression were performed to determine adjusted infection risk for each type of spine procedure (primary vs revision) and surgical approach (anterior, posterior, combined anteroposterior), accounting for patient (for example, age, sex, comorbidities/Charlson Comorbidity Index [CCI], and state buy-in) and hospital (census region) characteristics. RESULTS At 10 years, the overall infection incidence, including superficial and deep infections, was 8.5% in primary procedures and 12.2% in revisions. Among the factors considered, infection risk within 10 years was most influenced by comorbidities: for a CCI of 5 versus 0, the adjusted hazard ratio (AHR) was 2.48 (95% CI 1.93-3.19, p < 0.001); for ≥ 9 versus 2-3 fused vertebrae, the AHR was 2.39 (95% CI 1.20-4.76, p < 0.001); for revision versus primary fusion procedures, the AHR was 1.66 (95% CI 1.28-2.15, p < 0.001). Other significant predictors of 10-year infection risk included diagnosis of obesity (p < 0.001); state buy-in--a proxy for socioeconomic status (p = 0.02); age (p = 0.003); surgical approach (p = 0.03); census region (p = 0.02); and the year of the index procedure (p = 0.03). CONCLUSIONS Patient comorbidities were the greatest predictor of infection risk for the Medicare population. The high incidence of infection following instrumented fusion warrants increased focus on infection risk mitigation, especially for patients with comorbid conditions.

Femoral Nerve Block Versus Long-Acting Wound Infiltration in Total Knee Arthroplasty

Inverse associations between dairy consumption and CVD have been reported in several epidemiological studies. Our objective was to conduct a meta-analysis of prospective cohort studies of dairy intake and CVD. A comprehensive literature search was conducted to identify studies that reported risk estimates for total dairy intake, individual dairy products, low/full-fat dairy intake, Ca from dairy sources and CVD, CHD and stroke. Random-effects meta-analyses were used to generate summary relative risk estimates (SRRE) for high v. low intake and stratified intake dose-response analyses. Additional dose-response analyses were performed. Heterogeneity was examined in sub-group and sensitivity analyses. In total, thirty-one unique cohort studies were identified and included in the meta-analysis. Several statistically significant SRRE below 1.0 were observed, namely for total dairy intake and stroke (SRRE=0·91; 95% CI 0·83, 0·99), cheese intake and CHD (SRRE=0·82; 95% CI 0·72, 0·93) and stroke (SRRE=0·87; 95% CI 0·77, 0·99), and Ca from dairy sources and stroke (SRRE=0·69; 95% CI 0·60, 0·81). However, there was little evidence for inverse dose-response relationships between the dairy variables and CHD and stroke after adjusting for within-study covariance. The results of this meta-analysis of prospective cohort studies have shown that dairy consumption may be associated with reduced risks of CVD, although additional data are needed to more comprehensively examine potential dose-response patterns.

Meta-analysis of long-chain omega-3 polyunsaturated fatty acids (LCω-3PUFA) and prostate cancer

Electronic medical records (EMRs) are used increasingly for research in clinical oncology, epidemiology, and comparative effectiveness research (CER). Objective To assess the utility of using EMR data in population-based cancer research by comparing a database of EMRs from community oncology clinics against Surveillance Epidemiology and End Results (SEER) cancer registry data and two claims databases (Medicare and commercial claims). Study design and setting Demographic, clinical, and treatment patterns in the EMR, SEER, Medicare, and commercial claims data were compared using six tumor sites: breast, lung/bronchus, head/neck, colorectal, prostate, and non-Hodgkin’s lymphoma (NHL). We identified various challenges in data standardization and selection of appropriate statistical procedures. We describe the patient and clinic inclusion criteria, treatment definitions, and consideration of the administrative and clinical purposes of the EMR, registry, and claims data to address these challenges. Results Sex and 10-year age distributions of patient populations for each tumor site were generally similar across the data sets. We observed several differences in racial composition and treatment patterns, and modest differences in distribution of tumor site. Conclusion Our experience with an oncology EMR database identified several factors that must be considered when using EMRs for research purposes or generalizing results to the US cancer population. These factors were related primarily to evaluation of treatment patterns, including evaluation of stage, geographic location, race, and specialization of the medical facilities. While many specialty EMRs may not provide the breadth of data on medical care, as found in comprehensive claims databases and EMR systems, they can provide detailed clinical data not found in claims that are extremely important in conducting epidemiologic and outcomes research.

Epidemiology of Total Hip and Knee Arthroplasty Infection

Pain after total joint arthroplasty (TJA) can be severe and difficult to control. A single-dose local analgesic delivers bupivacaine in a liposomal time-release platform. In 2248 consecutive patients with hip and knee arthroplasty, half (Pre) were treated using a well-established multimodal analgesia, including periarticular injection (PAI), and half had the PAI substituted for a liposomal bupivacaine injection technique (Post). Pain scores were significantly lower for patients in the Post group for both hip and knee procedures. A large series of patients who had TJA experienced pain relief after the introduction of liposomal bupivacaine as part of an established multimodal protocol.

An analysis of fatal and non-fatal injuries and injury severity factors among electric power industry workers.

To develop a quantitative exposure-response relationship between concentrations and durations of inhaled diesel engine exhaust (DEE) and increases in lung cancer risks, we examined the role of temporal factors in modifying the estimated effects of exposure to DEE on lung cancer mortality and characterized risk by mine type in the Diesel Exhaust in Miners Study (DEMS) cohort, which followed 12,315 workers through December 1997. We analyzed the data using parametric functions based on concepts of multistage carcinogenesis to directly estimate the hazard functions associated with estimated exposure to a surrogate marker of DEE, respirable elemental carbon (REC). The REC-associated risk of lung cancer mortality in DEMS is driven by increased risk in only one of four mine types (limestone), with statistically significant heterogeneity by mine type and no significant exposure-response relationship after removal of the limestone mine workers. Temporal factors, such as duration of exposure, play an important role in determining the risk of lung cancer mortality following exposure to REC, and the relative risk declines after exposure to REC stops. There is evidence of effect modification of risk by attained age. The modifying impact of temporal factors and effect modification by age should be addressed in any quantitative risk assessment (QRA) of DEE. Until there is a better understanding of why the risk appears to be confined to a single mine type, data from DEMS cannot reliably be used for QRA.