Validation of a clinical prediction scale for hospital-onset Clostridium difficile infection.

OBJECTIVE: The aim of this study was to validate a clinical prediction scale for hospital-onset Clostridium difficile infection (CDI). METHODS: The study included a consecutive cohort of patients admitted to the adult medical service over a period of 17 months (June 2011 to October 2012). The clinical prediction scale comprised of new-onset loose stools (5 points), length of hospital stay >7days (4 points), aged 65 years or older (3 points), resides in long-term care facility (2 points), broad spectrum antibiotics use (1 point), and hypoalbuminemia (1 point). The hospital-onset CDI cases were defined as any new-onset diarrhea after 48 hours of hospital admission that tested positive on polymerase chain reaction assay for C. difficile toxin gene in the absence of history of CDI in the prior 8 weeks. The predictive performance of the scale was assessed using area under the receiver operating curve. RESULTS: A total of 10,357 patients were admitted to the medical service, of which, 7026 stayed in hospital beyond 48 hours. Mean (SD) age was 68.5 (18.2) years and 41.9% patients were male. A total of 1030 patients were tested for C. difficile toxin gene using polymerase chain reaction assay, of which, 159 patients were positive and 62 of them were unique hospital-onset CDI cases. The scale had area under the receiver operating curve of 0.94 [95% confidence interval (CI), 0.92-0.95]. At the cutoff score of 9, scale was 98.3% (95% CI, 90.2-99.9) sensitive and 85.2% (95% CI, 84.3-86.0) specific. CONCLUSIONS: Our study results support excellent predictive performance of a clinical prediction scale for hospital-onset CDI. This simple scale can be used in risk stratification leading to prompt tailoring of modifiable risk factors, empirical treatment, and use of probiotics.

A cohort study for derivation and validation of a clinical prediction scale for hospital-onset Clostridium difficile infection.

OBJECTIVE: To develop and validate a clinical prediction scale for hospital-onset Clostridium difficile infection (CDI). METHODS: A community-based, 360-bed hospital located in the suburbs of a metropolitan area in the United States served as the setting for the present retrospective cohort study. The cohort consisted of patients admitted to the adult medical service over a six-year period from October 2005 to September 2011. The cohort was divided into derivation (October 2005 to September 2009) and validation (October 2009 to September 2011) groups. The primary outcome measure was hospital-onset CDIs identified as stool positive for C difficile after 48 h of hospital admission ordered for new-onset unformed stool by the treating physician. RESULTS: In the derivation phase, 35,588 patients were admitted to the medical service and 21,541 stayed in hospital beyond 48 h. A total of 266 cases of CDI were identified, 121 of which were hospital onset. The developed clinical prediction scale included the onset of unformed stool (5 points), length of hospital stay beyond seven days (4 points), age >65 years (3 points), long-term care facility residence (2 points), high-risk antibiotic use (1 point) and hypoalbuminemia (1 point). The scale had an area under the receiver operating curve (AUC) of 0.93 (95% CI 0.82 to 0.94) in predicting hospital-onset CDI, with a sensitivity of 0.94 (95% CI 0.88 to 0.97) and a specificity of 0.80 (95% CI 0.79 to 0.80) at a cut-off score of 9 on the scale. During the validation phase, 16,477 patients were admitted, of whom 10,793 stayed beyond 48 h and 58 acquired CDI during hospitalization. The predictive performance of the score was maintained in the validation cohort (AUC 0.95 [95% CI 0.93 to 0.96]) and the goodness-to-fit model demonstrated good calibration. CONCLUSION: The authors developed and validated a simple clinical prediction scale for hospital-onset CDI. This score can be used for periodical evaluation of hospitalized patients for early initiation of contact precautions and empirical treatment once it is validated externally in a prospective manner.

Ticks and salt: an atypical case of neuroborreliosis.

It is well documented that central nervous system (CNS) infections may lead to syndrome of inappropriate anti-diuretic hormone secretion (SIADH), but diagnosing these can prove difficult in patients with atypical presentations. We present a case of SIADH and muscle weakness in a patient without typical signs of CNS infection who was tested and diagnosed with neuroborreliosis based largely on her likelihood of exposure. This case indicates the need for Lyme testing in patients with unexplained SIADH who live in endemic areas. The patient was an 83-year-old female with a history of type 2 diabetes and hypertension, who presented from her primary care physician's office when her sodium was found to be 123 mEq/L. Her sole symptom was proximal muscle weakness. The diagnosis of SIADH was reached based on laboratory data. A trial of fluid restriction was initiated, but neither her sodium nor her muscle weakness improved. Lyme testing was performed as the patient lived in an endemic area and was positive. Lumbar puncture showed evidence of neurologic involvement. After realizing the appropriate treatment for hyponatremia in this case, intravenous ceftriaxone was started, and patient's sodium levels improved and muscle weakness resolved. Studies show that SIADH is associated with CNS infections, likely related to the inflammatory cascade. However, the atypical presentation of neuroborreliosis for our patient delayed the appropriate diagnosis and treatment. Our case demonstrates the need to screen for Lyme disease in endemic areas in patients presenting with neurologic symptoms and SIADH.