The impact of ICD-9-CM code rank order on the estimated prevalence of Clostridium difficile infections.

Department of Medicine, Washington University School of Medicine, St Louis, Missouri 63110, USA.
Clinical Infectious Diseases (Impact Factor: 9.42). 07/2011; 53(1):20-5. DOI: 10.1093/cid/cir246
Source: PubMed

ABSTRACT US estimates of the Clostridium difficile infection (CDI) burden have utilized International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) diagnosis codes. Whether ICD-9-CM code rank order affects CDI prevalence estimates is important because the National Hospital Discharge Survey (NHDS) and the Nationwide Inpatient Sample (NIS) have varying limits on the number of ICD-9-CM codes collected.
ICD-9-CM codes for CDI (008.45), C. difficile toxin assay results, and dates of admission and discharge were collected from electronic hospital databases for adult patients admitted to 4 hospitals in the United States from July 2000 through June 2006. CDI prevalence per 1000 discharges was calculated and compared for NHDS and NIS limits and toxin assay results from the same hospitals. CDI prevalence estimates were compared using the χ(2) test, and the test of equality was used to compare slopes.
CDI prevalence measured by NIS criteria was significantly higher than that measured using NHDS criteria (10.7 cases per 1000 discharges versus 9.4 cases per 1000 discharges; P<.001) in the 4 hospitals. CDI prevalence measured by toxin assay results was 9.4 cases per 1000 discharges (P=.57 versus NHDS). However, the CDI prevalence increased more rapidly over time when measured according to the NHDS criteria than when measured according to toxin assay results (β=1.09 versus 0.84; P=.008).
Compared with the NHDS definition, the NIS definition captured 12% more CDI cases and reported significantly higher CDI rates. Rates calculated using toxin assay results were not different from rates calculated using NHDS criteria, but CDI prevalence appeared to increase more rapidly when measured by NHDS criteria than when measured by toxin assay results.

  • [Show abstract] [Hide abstract]
    ABSTRACT: Objectives Clostridium difficile infections (CDI) have increased over the last two decades, especially among cardiac surgical patients, who share many of the comorbidity risk factors for CDI. Our objectives were to use a large national database to 1) identify regional, hospital, patient, and procedure-level risk factors for CDI and 2) determine mortality, resource utilization, and cost of CDI in cardiac surgery. Methods Using the Nationwide Inpatient Sample (NIS) database, we identified 349,122 patients who underwent coronary artery bypass, valve, or thoracic-aortic surgery between 2004 and 2008. Of these, 2,581 (0.75%) were diagnosed with CDI. Multivariable regression analysis and propensity methodology were used for risk adjustment. Results Compared to the West, CDI was more likely to occur in the Northeast (OR=1.28, CI=1.12, 1.47) and Midwest (OR=1.27, CI=1.11, 1.46) and less likely in the South (OR=0.80, CI=0.70, 0.90). Medium-sized hospitals (OR=0.88, CI=0.78, 0.99) had a lower risk of CDI than large hospitals. Older age (>75 years [OR=2.59, CI=1.93, 3.49]), longer preoperative length of stay (OR=1.51, CI=1.43, 1.60), Medicare (OR=1.21, CI=1.05, 1.39) and Medicaid (OR=1.60, CI=1.31,1.96) coverage, and greater comorbidities were associated with CDI. Among matched pairs, patients with CDI had higher mortality (302 [12%] vs. 187 [7.2%], P<.001), longer median length of stay (21 vs. 11 days, P<.001), and higher median hospital charges ($193,330 vs. $112,245, P<.001). The cumulative incremental cost of CDI is an estimated $212 million/year. Conclusion CDI is associated with increased morbidity and resource utilization. Further work is needed to better understand the complex interplay between regional, hospital, and patient-level factors.
    The Journal of thoracic and cardiovascular surgery 11/2014; · 3.41 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Hematopoietic stem cell transplant (HSCT) recipients are at a high risk of Clostridium difficile-associated disease (CDAD) given frequent hospitalizations, prolonged antibiotic usage and altered integrity of intestinal mucosa. The prevalence and trends of CDAD in HSCT patients have not been extensively studied. In this study, the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes were used to identify CDAD in HSCT patients using a nationwide inpatient sample in the United States from 2000 to 2009. The prevalence of CDAD and in-hospital mortality in HSCT were investigated and compared to those without any transplants. Multivariate analysis was performed to identify if BMT and graft versus host disease (GVHD) were independently associated with mortality in CDAD patients. Of the 344,507 HSCT discharges, 4.7 % had CDAD. This was about 5 times higher when compared to non-transplant discharges. During engraftment admission, rates of CDAD were higher in allogenic group (8.4 vs. 5.7 %, p < 0.001). In subsequent admissions, those with GVHD had higher rates of CDAD (5.7 vs. 3.2 %, p < 0.001). On adjusted analysis in patients with CDAD, during engraftment admission, allogenic group had significantly higher mortality when compared with non-transplants (OR 3.7). Notably, there was no significant difference in mortality between patients with and without CDAD during the engraftment period for the allogeneic group. In subsequent admissions, there was higher mortality in those with GVHD (OR 4.8). Though the prevalence of CDAD in non-transplant population doubled (from 0.44 % in 2000 to 0.99 % in 2008), it has remained stable in HSCT patients (from 4.8 % in 2000 to 5.6 % in 2008). HSCT and GVHD are independently associated with CDAD though its presence does not affect mortality.
    International journal of hematology 04/2014; · 1.17 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The National Hospital Discharge Survey (NHDS) and the Nationwide Inpatient Sample (NIS) collect sample data and publish annual estimates of inpatient care in the United States, and both are commonly used in orthopaedic research. However, there are important differences between the databases, and because of these differences, asking these two databases the same question may result in different answers. The degree to which this is true for arthroplasty-related research has, to our knowledge, not been characterized.
    Clinical Orthopaedics and Related Research 08/2014; 472(11). · 2.88 Impact Factor


1 Download
Available from