Comparison of two computer algorithms to identify surgical site infections.

BACKGROUND: Surgical site infections (SSIs), the second most common healthcare-associated infections, increase hospital stay and healthcare costs significantly. Traditional surveillance of SSIs is labor-intensive. Mandatory reporting and new non-payment policies for some SSIs increase the need for efficient and standardized surveillance methods. Computer algorithms using administrative, clinical, and laboratory data collected routinely have shown promise for complementing traditional surveillance. METHODS: Two computer algorithms were created to identify SSIs in inpatient admissions to an urban, academic tertiary-care hospital in 2007 using the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes (Rule A) and laboratory culture data (Rule B). We calculated the number of SSIs identified by each rule and both rules combined and the percent agreement between the rules. In a subset analysis, the results of the rules were compared with those of traditional surveillance in patients who had undergone coronary artery bypass graft surgery (CABG). RESULTS: Of the 28,956 index hospital admissions, 5,918 patients (20.4%) had at least one major surgical procedure. Among those and readmissions within 30 days, the ICD-9-CM-only rule identified 235 SSIs, the culture-only rule identified 287 SSIs; combined, the rules identified 426 SSIs, of which 96 were identified by both rules. Positive and negative agreement between the rules was 36.8% and 97.1%, respectively, with a kappa of 0.34 (95% confidence interval [CI] 0.27-0.41). In the subset analysis of patients who underwent CABG, of the 22 SSIs identified by traditional surveillance, Rule A identified 19 (86.4%) and Rule B identified 13 (59.1%) cases. Positive and negative agreement between Rules A and B within these "positive controls" was 81.3% and 50.0% with a kappa of 0.37 (95% CI 0.04-0.70). CONCLUSION: Differences in the rates of SSI identified by computer algorithms depend on sources and inherent biases in electronic data. Different algorithms may be appropriate, depending on the purpose of case identification. Further research on the reliability and validity of these algorithms and the impact of changes in reimbursement on clinician practices and electronic reporting is suggested.

Using electronically available inpatient hospital data for research.

Despite a push to create electronic health records and a plethora of healthcare data from disparate sources, there are no data from a single electronic source that provide a full picture of a patient's hospital course. This paper describes a process to utilize electronically available inpatient hospital data for research. We linked several different sources of extracted data, including clinical, procedural, administrative, and accounting data, using patients' medical record numbers to compile a cohesive, comprehensive account of patient encounters. Challenges encountered included (1) interacting with distinct administrative units to locate data elements; (2) finding a secure, central location to house the data; (3) appropriately defining health measures of interest; (4) obtaining and linking these data to create a usable format for conducting research; and (5) dealing with missing data. Although the resulting data set is incredibly rich and likely to prove useful for a wide range of clinical and comparative effectiveness research questions, there are multiple challenges associated with linking hospital data to improve the quality of patient care.

A comparison of methods to detect urinary tract infections using electronic data.

BACKGROUND: The use of electronic medical records to identify common health care-associated infections (HAIs), including pneumonia, surgical site infections, bloodstream infections, and urinary tract infections (UTIs), has been proposed to help perform HAI surveillance and guide infection prevention efforts. Increased attention on HAIs has led to public health reporting requirements and a focus on quality improvement activities around HAIs. Traditional surveillance to detect HAIs and focus prevention efforts is labor intensive, and computer algorithms could be useful to screen electronic data and provide actionable information. METHODS: Seven computer-based decision rules to identify UTIs were compared in a sample of 33,834 admissions to an urban academic health center. These decision rules included combinations of laboratory data, patient clinical data, and administrative data (for example, International Statistical Classification of Diseases and Related Health Problems, Ninth Revision [ICD-9] codes). RESULTS: Of 33,834 hospital admissions, 3,870 UTIs were identified by at least one of the decision rules. The use of ICD-9 codes alone identified 2,614 UTIs. Laboratory-based definitions identified 2,773 infections, but when the presence of fever was included, only 1,125 UTIs were identified. The estimated sensitivity of ICD-9 codes was 55.6% (95% confidence interval [CI], 52.5%-58.5%) when compared with a culture- and symptom-based definition. Of the UTIs identified by ICD-9 codes, 167/1,125 (14.8%) also met two urine-culture decision rules. DISCUSSION: Use of the example of UTI identification shows how different algorithms may be appropriate, depending on the goal of case identification. Electronic surveillance methods may be beneficial for mandatory reporting, process improvement, and economic analysis.

Impact of immigration on the clinical expression of systemic lupus erythematosus: a comparative study of Hispanic patients residing in the USA and Mexico.

OBJECTIVE: To compare the socio-economic characteristics, clinical features and health-related quality of life in Hispanic SLE patients residing in Mexico and in the Southwest USA (Mexican and Texan, herein). METHODS: Mexican and Texan SLE patients (fulfilling ACR criteria) participating in separate longitudinal outcome studies were evaluated. Texan patients were randomly chosen to match total disease duration with the Mexican patients. Cross-sectional data for the Mexican patients were obtained by a US-trained investigator who had previously participated in data collection for the cohort to which the Texan patients belonged. Socio-economic and -demographic characteristics, clinical characteristics, disease activity (with SLAM-Revised), damage accrual (with SLICC/ACR Damage Index) and self-reported function (with Short Form-36) were compared between the two groups. RESULTS: Seventy Mexican patients were matched with either one or two Texan patients (n = 94) for a total of 164 patients. Mexican patients were younger. In age-adjusted analyses, the Mexican patients were more educated, had better health-related quality of life and overall less systemic SLE manifestations. Mexican patients were exposed more frequently to AZA. CONCLUSIONS: Texan patients had more severe disease than the Mexican patients. In multivariable analyses, Texan Hispanic ethnicity was significantly associated with high disease activity, but significance was not reached for damage. The discrepant findings observed between these two Hispanic groups of SLE patients may reflect socio-economic or biological factors. Given the global phenomenon of immigration, rheumatologists should be aware of the overall course and outcome of immigrant SLE patients if undesirable outcomes are to be prevented.

Features associated with, and the impact of, hemolytic anemia in patients with systemic lupus erythematosus: LX, results from a multiethnic cohort.

OBJECTIVE: To examine the clinical and genetic correlates of hemolytic anemia and its impact on damage accrual and mortality in systemic lupus erythematosus (SLE) patients. METHODS: SLE patients (American College of Rheumatology [ACR] criteria) of Hispanic (Texan or Puerto Rican), African American, and Caucasian ethnicity from the LUMINA (LUpus in MInorities, NAture versus nurture) cohort were studied. Hemolytic anemia was defined as anemia with reticulocytosis (ACR criterion). The association between degrees of hemolytic anemia and socioeconomic/demographic, clinical, pharmacologic, immunologic, psychological, and behavioral variables was examined by univariable and multivariable (proportional odds model) analyses. Genetic variables (FCGR and Fas/Fas ligand polymorphisms) were examined by 2 degrees of freedom test of association and Cochran-Armitage trend tests. The impact of hemolytic anemia on damage accrual and mortality was examined by multivariable linear and Cox regression analyses, respectively. RESULTS: Of 628 patients studied, 90% were women, 19% were Texan Hispanic, 16% were Puerto Rican Hispanic, 37% were African American, and 28% were Caucasian. Sixty-five (10%) patients developed hemolytic anemia at some time during the disease course, 83% at or before diagnosis. Variables independently associated with degrees of hemolytic anemia were African American ethnicity, thrombocytopenia, and the use of azathioprine. Hemolytic anemia was associated with damage accrual after adjusting for variables known to affect this outcome; however, hemolytic anemia was not associated with mortality. CONCLUSION: The association of hemolytic anemia with thrombocytopenia suggests a common mechanism in their pathophysiology. Hemolytic anemia is an early disease manifestation and is associated with African American ethnicity and the use of azathioprine; it appears to exert an impact on damage but not on mortality.

Using the Short Form 6D, as an overall measure of health, to predict damage accrual and mortality in patients with systemic lupus erythematosus: XLVII, results from a multiethnic US cohort.

OBJECTIVE: To determine if overall health status as assessed by the Short Form 6D (SF-6D) index, a preference-based generic measure of health, is associated with the occurrence of damage accrual and mortality in patients with systemic lupus erythematosus (SLE). METHODS: We studied SLE patients (American College of Rheumatology criteria) from the LUpus in MInorities, NAture versus nurture cohort (LUMINA), a longitudinal multiethnic cohort. The contribution of the SF-6D as assessed at enrollment to damage accrual at the last visit and mortality was examined. All variables previously shown to be determinants of damage accrual and mortality and corroborated by univariable analyses were adjusted for in multivariable models (Poisson and Cox proportional hazards regressions, respectively). Damage accrual and mortality were the dependent variables. Similar analyses were performed examining the associations of the Short Form 36 summary measures (physical component summary [PCS], mental component summary [MCS]) with these outcomes. RESULTS: In 552 patients, the SF-6D was negatively associated with damage accrual and mortality in the univariable analyses; the association with damage was confirmed in the multivariable analyses (chi(2) = 9.020, P = 0.002) but the association with mortality was not confirmed (hazard ratio 0.495, 95% confidence interval 0.041-6.038). When the PCS and MCS were evaluated, the PCS, but not the MCS, was found to be associated with damage but not with mortality. CONCLUSION: The SF-6D (and the PCS) as measured early in the disease course were found to independently predict damage accrual at the last visit, but not mortality. Although the SF-6D was originally conceived as a utility measure, it may be used to accurately assess overall health status in patients with SLE.

The impact of increased body mass index on systemic lupus erythematosus: data from LUMINA, a multiethnic cohort (LUMINA XLVI) [corrected].

OBJECTIVE: The aim of this study was to examine the impact of an increased body mass index (BMI) on disease activity, damage accrual, fatigue, self-reported health-related quality of life (HRQOL), and fibromyalgia in patients with lupus using longitudinal data from LUMINA, a large multiethnic cohort. METHODS: SLE patients (>/=4 ACR revised criteria), /=30 kg/m). An increased BMI was associated with older age, less social support, higher degree of helplessness, depression, more abnormal illness-related behaviors, poorer self-reported HRQOL, fatigue, and fibromyalgia, but not with disease activity or damage accrual by univariable analyses. In multivariable analyses, BMI was independently associated with fibromyalgia but not with disease activity, fatigue, or self-reported HRQOL. CONCLUSIONS: An increased BMI is independently associated with presence of fibromyalgia but not with disease activity, damage accrual, fatigue or self-reported quality of life in patients with SLE. Optimizing weight merits investigation to see if it can significantly impact this pervasive SLE-associated manifestation.

Systemic lupus erythematosus in a multiethnic US cohort: XLIII. The significance of thrombocytopenia as a prognostic factor.

OBJECTIVE: To examine the clinical correlates of thrombocytopenia and the value of thrombocytopenia as a predictor of disease activity, damage accrual, and mortality in patients with systemic lupus erythematosus (SLE). METHODS: SLE patients participating in a longitudinal multiethnic cohort were studied. Thrombocytopenia was defined as a platelet count <100,000/mm(3) at or before enrollment (baseline). Patients were categorized by the presence and absence of thrombocytopenia. The impact of thrombocytopenia as well as severe thrombocytopenia (platelet count <50,000/mm(3)) on disease activity, damage accrual, and mortality was examined by multivariable analyses. RESULTS: A total of 616 patients were studied; 121 of the patients (20%) had thrombocytopenia, of whom 30 had severe thrombocytopenia. By univariable analyses, those with thrombocytopenia had more pulmonary, neurologic, renal, and hematologic involvement, worse disease activity and damage, and higher mortality rates. By multivariable analyses, thrombocytopenia was associated with higher disease activity over the disease course (P = 0.018), but not with the accrual of damage either at baseline (P = 0.543) or at the last visit (P = 0.086); however, severe thrombocytopenia was associated with damage accrual at the last visit (P = 0.020). When poverty was not included in the models, thrombocytopenia (<100,000/mm(3) or <50,000/mm(3)) was strongly associated with mortality (P < 0.001 for each comparison); however, the level of significance decreased some when poverty was included in the models. CONCLUSION: Thrombocytopenia early in the course of SLE is indicative of more severe and active disease. Severe thrombocytopenia is an independent predictor of damage accrual at the last visit. Thrombocytopenia is also an independent predictor of mortality, albeit of a lesser magnitude than that predicted by poverty. Patients with thrombocytopenia need close monitoring for possible undesirable outcomes.

Accelerated damage accrual among men with systemic lupus erythematosus: XLIV. Results from a multiethnic US cohort.

OBJECTIVE: To determine the impact of the patient's sex on the manifestations and outcome of systemic lupus erythematosus (SLE). METHODS: We studied SLE patients who were ages 16 years or older and had a disease duration of < or =5 years at the time of enrollment in the LUpus in MInorities, NAture versus nurture cohort, a multiethnic cohort consisting of Hispanic, African American, and Caucasian patients. Socioeconomic/demographic, clinical, and serologic features, as well as disease activity (by the Systemic Lupus Activity Measure, Revised) and damage accrual (by the Systemic Lupus International Collaborating Clinics/American College of Rheumatology Damage Index) were compared between male and female patient groups. Multivariable analyses using male sex and damage accrual as dependent variables were then performed. RESULTS: Sixty-three male SLE patients (10.2%) from all ethnic groups were included. The mean ages of the male and female patients were comparable. Factors that were either more frequent or tended to be more frequent among male SLE patients were Caucasian ethnicity, smoking, alcohol use, lupus anticoagulant (LAC) positivity, and renal involvement, whereas musculoskeletal involvement was less common. American College of Rheumatology criteria accrual time and disease duration were shorter in the male patients; damage was more common and of higher magnitude in this group. LAC positivity, shorter disease duration, and higher early damage scores were independently associated with male SLE. Male sex was a strong predictor of baseline damage, measured as a categorical variable (t-test = 2.357, beta-standardized coefficient 0.113; P = 0.019) or a continuous variable (hazard ratio 3.179 [95% confidence interval 1.999-5.056]; P < 0.001). Male sex was also positively associated with the development of damage over most of the course of the disease. CONCLUSION: Poorer long-term prognosis among men with SLE appears to be decisively determined by their accelerated development of damage, particularly early in the course of the disease.

African-American and Hispanic ethnicities, renal involvement and obesity predispose to hypertension in systemic lupus erythematosus: results from LUMINA, a multiethnic cohort (LUMINAXLV).

OBJECTIVE: To examine the predictors of the occurrence of hypertension in a large multiethnic US cohort. PATIENTS AND METHODS: There were 614 patients with systemic lupus erythematoses (SLE; > or = 4 American College of Rheumatology revised criteria) with < or = 5 years of disease duration at entry into the cohort (T0) and of Hispanic (Texan or Puerto Rican), African-American or Caucasian ethnicity. T0 variables were compared between patients who did and did not develop hypertension (blood pressure > or = 140/90 mm Hg on at least two occasions and/or the use of antihypertensive drugs) after T0. Significant and clinically relevant variables were then examined by a stepwise logistic regression model. RESULTS: A total of 379 patients without hypertension at T0 were included (patients who developed hypertension prior to SLE diagnosis (n = 126) or before T0 (n = 109) were excluded). Predictors of hypertension were African-American and Texan-Hispanic ethnicities, renal involvement and a higher body mass index. CONCLUSIONS: Traditional cardiovascular risk factors, disease-related factors and ethnicity play a role in the occurrence of hypertension in patients with SLE. Controlling renal involvement and optimising body weight may prevent the occurrence of hypertension.