Validation of an International Classification of Diseases, Ninth Revision Code Algorithm for Identifying Chiari Malformation Type 1 Surgery in Adults

Jacob K. Greenberg, Travis R. Ladner, Margaret A. Olsen, Chevis N. Shannon, Jingxia Liu, Chester K. Yarbrough, Jay F. Piccirillo, John C. Wellons, Matthew D. Smyth, Tae Sung Park, David D. Limbrick

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

BACKGROUND: The use of administrative billing data may enable large-scale assessments of treatment outcomes for Chiari Malformation type I (CM-1). However, to utilize such data sets, validated International Classification of Diseases, Ninth Revision (ICD-9-CM) code algorithms for identifying CM-1 surgery are needed. OBJECTIVE: To validate 2 ICD-9-CM code algorithms identifying patients undergoing CM-1 decompression surgery. METHODS: We retrospectively analyzed the validity of 2 ICD-9-CM code algorithms for identifying adult CM-1 decompression surgery performed at 2 academic medical centers between 2001 and 2013. Algorithm 1 included any discharge diagnosis code of 348.4 (CM-1), as well as a procedure code of 01.24 (cranial decompression) or 03.09 (spinal decompression, or laminectomy). Algorithm 2 restricted this group to patients with a primary diagnosis of 348.4. The positive predictive value (PPV) and sensitivity of each algorithm were calculated. RESULTS: Among 340 first-time admissions identified by Algorithm 1, the overall PPV for CM-1 decompression was 65%. Among the 214 admissions identified by Algorithm 2, the overall PPV was 99.5%. The PPV for Algorithm 1 was lower in the Vanderbilt (59%) cohort, males (40%), and patients treated between 2009 and 2013 (57%), whereas the PPV of Algorithm 2 remained high (≥99%) across subgroups. The sensitivity of Algorithms 1 (86%) and 2 (83%) were above 75% in all subgroups. CONCLUSION: ICD-9-CM code Algorithm 2 has excellent PPV and good sensitivity to identify adult CM-1 decompression surgery. These results lay the foundation for studying CM-1 treatment outcomes by using large administrative databases.

Original languageEnglish
Pages (from-to)269-273
Number of pages5
JournalNeurosurgery
Volume77
Issue number2
DOIs
StatePublished - Aug 20 2015

Keywords

  • Administrative data research
  • Chiari malformation type 1
  • Health services research
  • Neurosurgery
  • Validation studies

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