Comparing diagnostic coding and laboratory results.
We identified SADRs and SIDRs coded for malaria, syphilis, acute hepatitis B, and Lyme disease in sailors, marines, and their family members, who were beneficiaries for medical care in a large metropolitan area. Medical encounters from January 1, 2001, to June 30, 2002, were studied. All records for the same patient with the same diagnostic code(s) were considered as 1 encounter. Records were selected on the basis of International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes (4) as defined by the Department of Defense (5). Laboratory data were not part of SIDRs and SADRs but were part of CHCS.
For records with diagnostic codes relating to any of the 4 diseases of interest, laboratory records were searched to determine: 1) whether the provider ordered an appropriate test or tests and 2) if these were ordered, were the test results confirmatory (positive). Appropriate and confirmatory test results were determined by using published references (5-7) and local laboratory practices. For malaria, a blood smear was considered an appropriate test with a positive blood smear accepted as confirmatory (5,6). We considered both nontreponemal and treponemal tests to be appropriate for syphilis but only a positive treponemal test as confirmatory (5,6). For acute hepatitis B, we considered hepatitis B surface antigen or immunoglobulin (Ig) M anti-hepatitis B core (anti-HBc) to be an appropriate test, but only a positive IgM anti-HBc was accepted as confirmatory (5,6). We considered enzyme immunoassay total antibody screens or Western blot (WB) IgG or IgM tests to be appropriate for Lyme disease and accepted any positive test as confirmatory (5-7).) [chi square] calculations were conducted ([alpha] = 0.05).
Twenty-one SIDRs and 155 SADRs met the selection criteria (Table). While 61.9% of SIDRs studied had appropriate laboratory tests ordered, only 19.0% had associated confirmatory results in CHCS. For outpatient records, 64.5% had appropriate tests ordered, and 15.5% had confirmatory results. Among the SADRs, the proportions of appropriate laboratory tests for the diseases studied differed significantly (summary [chi square] =11.5, p = 0.01). These results suggest that tracking electronic SADR and SIDR datasets for the selected reportable diseases could produce a high number of false-positive reports; in this study, 81.0% of inpatient and 84.5% of outpatient reports would lack a confirmatory laboratory test result.
This initial evaluation is limited but supports the need to evaluate electronic datasets before using them for medical surveillance. We examined only ICD-9-CM coded records of selected diseases from 1 geographic area, with resulting small samples. Therefore, our results may not be generalizable. This study was restricted to laboratory, inpatient, and outpatient data recorded within 1 coordinated military system. Laboratory testing or clinical visits may have occurred outside of this network and may not have been captured in this study. Laboratory data were not recorded or stored in a standardized format in CHCS, increasing the likelihood of misclassification. We did not evaluate all related sources of data, including the hard-copy clinical records, so we do not know the completeness of the ICD-9-CM codes or the extent of ICD-9-CM code misclassification. Additionally, local clinical practices in terms of both ordering laboratory tests and coding diagnoses for the diseases studied were not defined.
Future studies would benefit from comparing reported medical events, paper medical records, and electronic datasets to include determination of sensitivity as well as positive predictive value (2,8,9). Discordance in these data sources should be investigated for miscoding, incomplete data, and unexpected clinical practices.
Efforts to improve medical record coding at military medical treatment facilities are under way (10). Additionally, standardization of CHCS laboratory test files, including adoption of the Logical Observation Identifiers Names and Codes system for standardized reporting of test names, is under way (available from http://www.ha.osd.mil/policies/2003/03-023.pdf). However, a documented, complete, reliable, and closely monitored single source of data for medical surveillance and disease reporting does not currently exist. Therefore, surveillance programs for infectious diseases in the US military should include monitoring of multiple, related sources of data and information (e.g., electronic inpatient and outpatient encounters, laboratory results, and pharmacy data). All of these sources should be evaluated for completeness and accuracy.
Table. Clinical records with associated laboratory test results * Inpatient records (SIDR) No. No. Confirmatory records No. tests results (%) Disease ([dagger]) selected ordered (%) ([double dagger]) Malaria 3 3 (100.0) 1 (33.3) Syphilis 1 1 (100.0) 1 (100.0) Acute hepatitis B 16 8 (50.0) 1 (6.3) Lyme disease 1 1 (100.0) 1 (100.0) Total 21 13 (61.9) 4 (19.0) Outpatient records (SADR) No. records No. Tests Disease ([dagger]) selected ordered (%) (section) Malaria 17 8 (47.1) Syphilis 44 31 (70.4) Acute hepatitis B 39 32 (82.1) Lyme disease 55 29 (52.7) Total 155 100 (64.5) Outpatient records (SADR) No. confirmatory Disease ([dagger]) results (%) ([double dagger]) ([paragraph]) Malaria 1 (5.9) Syphilis 12 (27.3) Acute hepatitis B 5 (12.8) Lyme disease 6 (10.9) Total 24 (15.5) * This table presents Standard Inpatient Data Records (SIDR) and Standard Ambulatory Data Records (SADR) studied and percentages with appropriate laboratory tests ordered and confirmatory laboratory test results. ([dagger]) International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes: malaria, 084.0-084.6; syphilis, 090, 091, 095, 096; acute hepatitis B, 070.30, 070.31; Lyme disease, 088.81. ([double dagger]) Percentages reported reflect the proportion of records that had positive confirmatory laboratory results. ([section]) Summary [chi square] = 11.5; p = 0.01. ([paragraph]) Summary [chi square] = 7.0; p = 0.07.
We thank the Army Medical Surveillance Activity and Tricare Management Activity for data support; and Shilpa Hakre, Danielle Dell, Cara Olsen, and Julie Pavlin for manuscript review.
This study was supported in part by the Department of Defense Global Emerging Infections Surveillance and Response System, Silver Spring, Maryland.
Asha J. Riegodedios, * Anuli Ajene, * Mark A. Malakooti, * Joel C. Gaydos, ([dagger]) Victor H. MacIntosh, ([dagger]) and Bruce K. Bohnker * (1)
* Navy Environmental Health Center, Portsmouth, Virginia, USA; and 1-Department of Defense Global Emerging Infections Surveillance and Response System, Silver Spring, Maryland, USA
(1) Preliminary findings were presented at the US Army Force Health Protection Conference, August 2003, Albuquerque NM, the International Conference on Emerging Infectious Diseases, February 2004, Atlanta, GA, and the Navy Occupational Health and Preventive Medicine Workshop, March 2004, Norfolk, VA.
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(4.) International Classification of Diseases, Ninth Revision, Clinical Modification. Dover (DE): American Medical Association; 1997.
(5.) Office of the Assistant Secretary of Defense. Health Affairs Memo of 18 Nov 1998. Triservice reportable disease document. [accessed 12 Jan 2004]. Available from http://www.tricare.osd.mil/policy/fy98/ TriService_Reportable_Events Document.pdf
(6.) Isada CM, Kasten BL, Goldman MP, Gray LD, Aberg JA. Infectious diseases handbook. 5th ed. Hudson (OH): Lexi-Comp Inc; 2003.
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(9.) Yokoe DS, Subramanyan GS, Nardell E, Sharnprapai S, McCray E, Platt R. Supplementing tuberculosis surveillance with automated data from health maintenance organizations. Emerg Infect Dis. 1999;5:779-87.
(10.) Office of the Secretary of Defense- Health Affairs Memorandum of 20 Aug 2003. Improved medical record coding at military healthcare facilities. [accessed 20 Mar 2004]. Available from http://www.pasba. amedd.army.mil/Quality/Resources/MemoI mprovingMRCoding.pdf
Address for correspondence: Asha J. Riegodedios, Navy Environmental Health Center, c/o Naval Dosimetry Center, 8901 Wisconsin Ave, Bethesda, Maryland 20889, USA; fax: 301-295-5981; email: firstname.lastname@example.org
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|Author:||Bohnker, Bruce K.|
|Publication:||Emerging Infectious Diseases|
|Article Type:||Letter to the Editor|
|Date:||Jul 1, 2005|
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