Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2015 Jun 22;5(6):e007520.
doi: 10.1136/bmjopen-2014-007520.

Validity and Reliability of Chronic Tic Disorder and Obsessive-Compulsive Disorder Diagnoses in the Swedish National Patient Register

Affiliations
Free PMC article

Validity and Reliability of Chronic Tic Disorder and Obsessive-Compulsive Disorder Diagnoses in the Swedish National Patient Register

Christian Rück et al. BMJ Open. .
Free PMC article

Abstract

Objectives: The usefulness of cases diagnosed in administrative registers for research purposes is dependent on diagnostic validity. This study aimed to investigate the validity and inter-rater reliability of recorded diagnoses of tic disorders and obsessive-compulsive disorder (OCD) in the Swedish National Patient Register (NPR).

Design: Chart review of randomly selected register cases and controls.

Method: 100 tic disorder cases and 100 OCD cases were randomly selected from the NPR based on codes from the International Classification of Diseases (ICD) 8th, 9th and 10th editions, together with 50 epilepsy and 50 depression control cases. The obtained psychiatric records were blindly assessed by 2 senior psychiatrists according to the criteria of the fourth edition of the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, Text Revision (DSM-IV-TR) and ICD-10.

Primary outcome measurement: Positive predictive value (PPV; cases diagnosed correctly divided by the sum of true positives and false positives).

Results: Between 1969 and 2009, the NPR included 7286 tic disorder and 24,757 OCD cases. The vast majority (91.3% of tic cases and 80.1% of OCD cases) are coded with the most recent ICD version (ICD-10). For tic disorders, the PPV was high across all ICD versions (PPV=89% in ICD-8, 86% in ICD-9 and 97% in ICD-10). For OCD, only ICD-10 codes had high validity (PPV=91-96%). None of the epilepsy or depression control cases were wrongly diagnosed as having tic disorders or OCD, respectively. Inter-rater reliability was outstanding for both tic disorders (κ=1) and OCD (κ=0.98).

Conclusions: The validity and reliability of ICD codes for tic disorders and OCD in the Swedish NPR is generally high. We propose simple algorithms to further increase the confidence in the validity of these codes for epidemiological research.

Keywords: Registries.

Figures

Figure 1
Figure 1
Annual incidence of tic disorders in the Swedish National Patient Register. Black bars: number of new cases diagnosed from 1969 to 2000 (inpatients only). White bars: number of new cases diagnosed from 2001 to 2009 (inpatients and outpatients).
Figure 2
Figure 2
Annual incidence of obsessive-compulsive disorder in the Swedish National Patient Register. Black bars: number of new cases diagnosed from 1969 to 2000 (inpatients only). White bars: number of new cases diagnosed from 2001 to 2009 (inpatients and outpatients).

Similar articles

See all similar articles

Cited by 23 articles

See all "Cited by" articles

References

    1. Ludvigsson JF, Andersson E, Ekbom A et al. External review and validation of the Swedish national inpatient register. BMC Public Health 2011;11:450 10.1186/1471-2458-11-450 - DOI - PMC - PubMed
    1. Ludvigsson JF, Otterblad-Olausson P, Pettersson BU et al. The Swedish personal identity number: possibilities and pitfalls in healthcare and medical research. Eur J Epidemiol 2009;24:659–67. 10.1007/s10654-009-9350-y - DOI - PMC - PubMed
    1. Karno M, Golding JM, Sorenson SB et al. The epidemiology of obsessive-compulsive disorder in five us communities. Arch Gen Psychiatry 1988;45:1094–9. 10.1001/archpsyc.1988.01800360042006 - DOI - PubMed
    1. American Psychiatric Association. Diagnostic and statistical manual of mental disorders: DSM-IV-TR. 4th edn Washington DC: American Psychiatric Association, 2000.
    1. Scharf JM, Miller LL, Gauvin CA et al. Population prevalence of Tourette syndrome: a systematic review and meta-analysis. Mov Disord 2015;30:221–8. 10.1002/mds.26089 - DOI - PubMed

Publication types

Feedback