Predicting the risk of Clostridium difficile infection following an outpatient visit: development and external validation of a pragmatic, prognostic risk score.

Increasing morbidity related to Clostridium difficile infection (CDI) has heightened interest in the identification of patients who would most benefit from recognition of risk and intervention. We sought to develop and validate a prognostic risk score to predict CDI risk for individual patients following an outpatient healthcare visit. We assembled a cohort of Kaiser Permanente Northwest (KPNW) patients with an index outpatient visit between 2005 and 2008, and identified CDI in the year following that visit. Applying Cox regression, we synthesized a priori predictors into a CDI risk score, which we validated among a Kaiser Permanente Colorado (KPCO) cohort. We calculated and plotted the observed 1-year CDI risk for each decile of predicted risk for both cohorts. Among 356 920 KPNW patients, 608 experienced CDI, giving a 1-year incidence of 2.2 CDIs per 1000 patients. The Cox model differentiated between patients who do and do not develop CDI: there was a C-statistic of 0.83 for KPNW. The simpler points-based risk score, derived from the Cox model, was validated successfully among 296 550 KPCO patients, with no decline in the area under the receiver operating characteristic curve: 0.785 (KPNW) vs. 0.790 (KPCO). The predicted risk for CDI agreed closely with the observed risk. Our CDI risk score utilized data collected during usual care to successfully identify patients who developed CDI, discriminating them from patients at the lowest risk for CDI. Our prognostic CDI risk score provides a decision-making tool for clinicians in the outpatient setting.

Risk of progression of nephropathy in a population-based sample with type 2 diabetes.

AIMS: Progression through stages of nephropathy has not been well described in a large, well-characterized, population-based study. Our aims were to describe the progression of nephropathy and identify characteristics associated with progression in a U.S. population-based sample. METHODS: We identified 10,290 members of a managed care organization who had hypertension and type 2 diabetes, a urine albumin-to-creatinine ratio (UACR) measurement in 2001-2003, and at least 2 follow-up UACRs. Progression of nephropathy was defined as progression to a higher stage of nephropathy than was present at baseline. RESULTS: At baseline, 57% had normoalbuminuria, 31% had microalbuminuria, and 12% had macroalbuminuria. The incidence of nephropathy progression (per 1000 person-years) was 94.7, 35.1, and 6.5 for normo-, micro-, and macro-albuminuria, respectively. ACEi/ARB use ranged from 61-67%, except among patients with macroalbuminuria at follow-up. Age, diabetes duration, and A1C were significant predictors of progression. CONCLUSIONS: Our study, one of the first to examine the progression of nephropathy in a U.S. population-based sample, showed that among adults with diabetes and hypertension, the burden of nephropathy and its progression may be greater than previously reported. Further, the use of ACEi/ARBs was not optimal.

Secular trends in kidney disease: is the decreased incidence of renal replacement therapy due to a decrease in chronic kidney disease incidence?

AIMS: Little is known about trends in renal replacement therapy among patients with chronic kidney disease (CKD) or about changes in the incidence of CKD. We studied the incidence of renal replacement therapy within the population of a health maintenance organization (HMO) both among the entire HMO population and among those with CKD. METHODS: We calculated yearly incidence rates of renal replacement therapy for each year from 1998 to 2005. We defined CKD using the National Kidney Foundation definition of 2 estimated glomerular filtration rates below 60 ml/min/1.73 m2 90 or more days apart. Poisson regression assessed year-to-year differences. RESULTS: The number of patients with CKD rose consistently from 3,861 in 1998 to 5,242 in 2005. The proportion of patients who had been diagnosed with hypertension rose from 86.7% (starting renal replacement therapy) or 34.5% (with CKD) to 99.1 and 46.9%. The proportion of patients with diabetes changed little throughout the years studied. The mean estimated glomerular filtration rate among CKD patients rose minimally from 38.4 ml/min/1.73 m2 in 1998 to 39.9 ml/min/1.73 m2 in 2005. Age- and sex-adjusted rates of RRT among patients with CKD varied (p=0.0034), but did not follow a consistent pattern over time. CONCLUSIONS: Incidence of renal replacement therapy among patients with CKD changed little between 1998 and 2005, despite an increase in the number of patients diagnosed with CKD. The discrepancy may be due to increased laboratory identification of CKD.

A study of the prevalence of significant increases in serum creatinine following angiotension-converting enzyme inhibitor administration.

Angiontension-converting enzyme inhibitors (ACEIs) are beneficial in the treatment of diabetic and nondiabetic kidney disease, coronary artery disease and congestive heart failure. One adverse effect of ACEIs use is a rise in serum creatinine and potential renal failure. This paper attempts to quantify this risk and assess the need for pre- and post-ACEI serum creatinine measurements. A computerized search of Kaiser Permanente Northwest's electronic medical record was conducted to find patients over the age of 40 years taking lisinopril between July 1, 2000 and June 30, 2002. Patient demographic information and presence in diabetes and coronary artery disease registries was collected. A subsequent search for pre- and postlisinopril serum creatinine levels within 6 months of initial lisinopril prescription was conducted. Patients with prelisinopril creatinine < or = 1.2 mg/dl and postlisinopril creatinine > 2.5 mg/dl underwent chart review to discern adverse events associated with the rise in serum creatinine. A total of 18,977 patients were prescribed lisinopril between July 1, 2000 and June 30, 2002. In all 13 166 patients had a pre- and postlisinopril creatinine checked. In all, 31 patients had a rise in creatinine from < or = 1.2 mg/dl to > 2.5 mg/dl (0.2%). Possible contributors to rise in creatinine included congestive heart failure, dehydration and infection. No patients developed end-stage renal disease, although three died. In conclusion, end-stage renal disease is an unlikely outcome among patients prescribed lisinopril and is most likely associated with other events.

A crossover study of gabapentin in treatment of restless legs syndrome among hemodialysis patients.

Restless legs syndrome (RLS) is a common entity affecting hemodialysis patients. Although the cause of RLS remains unclear, a number of therapies have been used successfully to treat the disorder. Gabapentin is an anticonvulsant shown to alleviate symptoms of RLS in two small studies of nonhemodialysis patients. Because it is excreted renally, gabapentin has a long half-life among hemodialysis patients and may be advantageous if proven effective. We conducted a randomized, double-blind, placebo-crossover study of gabapentin in the treatment of RLS among a population of hemodialysis patients. Sixteen patients identified with RLS were randomized to either gabapentin or placebo. After 6 weeks of treatment with 200 to 300 mg of gabapentin after each hemodialysis session, patients' RLS was reassessed. After a 1-week washout period, patients were switched from gabapentin to placebo or placebo to gabapentin. After another 6 weeks, patients' RLS was assessed again. Patient data were analyzed using both parametric and nonparametric means. Thirteen of the 16 original patients completed the study. Two patients dropped out because of lethargy (believed to be secondary to gabapentin), and 1 patient died secondary to myocardial infarction. Eleven patients responded to gabapentin, but not placebo (P < 0.01). One patient responded to both, and 1 patient responded to placebo, but not gabapentin. Gabapentin is an effective treatment for RLS in hemodialysis patients.