Evaluation of ICD-10 algorithms to identify hypopituitary patients in the Danish National Patient Registry

Abstract

Objective

Routinely collected health data may be valuable sources for conducting research. This study aimed to evaluate the validity of algorithms detecting hypopituitary patients in the Danish National Patient Registry (DNPR) using medical records as reference standard.

Study design and setting

Patients with International Classification of Diseases (10th edition [ICD-10]) diagnoses of hypopituitarism, or other diagnoses of pituitary disorders assumed to be associated with an increased risk of hypopituitarism, recorded in the DNPR during 2000–2012 were identified. Medical records were reviewed to confirm or disprove hypopituitarism.

Results

Hypopituitarism was confirmed in 911 patients. In a candidate population of 1,661, this yielded an overall positive predictive value (PPV) of 54.8% (95% confidence interval [CI]: 52.4–57.3). Using algorithms searching for patients recorded at least one, three or five times with a diagnosis of hypopituitarism (E23.0x) and/or at least once with a diagnosis of postprocedural hypopituitarism (E89.3x), PPVs gradually increased from 73.3% (95% CI: 70.6–75.8) to 83.3% (95% CI: 80.7–85.7). Completeness for the same algorithms, however, decreased from 90.8% (95% CI: 88.7–92.6) to 82.9% (95% CI: 80.3–85.3) respectively. Including data of hormone replacement in the same algorithms PPVs increased from 73.2% (95% CI: 70.6–75.7) to 82.6% (95% CI: 80.1–84.9) and completeness decreased from 94.3% (95% CI: 92.6–95.7) to 89.7% (95% CI: 87.5–91.6) with increasing records of E23.0x.

Conclusion

The DNPR is a valuable data source to identify hypopituitary patients using a search criteria of at least five records of E23.0x and/or at least one record of E89.3x. Completeness is increased when including hormone replacement data in the algorithm. The consequences of misclassification must, however, always be considered.

Keywords:

• ICD-10 algorithms
• registry health data
• hypopituitarism

Acknowledgments

The authors thank Novo Nordisk for an unrestricted research grant. The authors thank the following MDs throughout the Central Denmark Region for enabling access to medical records and data of hormone replacement: Andreas Kaal, Department of Internal Medicine, Region Hospital Horsens; Bent Windelborg Nielsen, Department of Pediatrics, Region Hospital Randers; Birgitte Hertz, Department of Pediatrics, Region Hospital Viborg; Bigitte Forsom Sandal, Department of Neurology, Region Hospital Holstebro; Britta Kremke, Department of Pediatrics, Region Hospital Randers; Carsten Byrjalsen, Hospital Unit West; Carsten Koch-Jensen, Department of Neurosurgery, Aarhus University Hospital; Charlotte Søndergaard, Department of Pediatrics, Region Hospital Herning; Else Marie Damsgaard, Department of Geriatrics, Aarhus University Hospital; Else Vestbo, Department of Endocrinology and Internal Medicine, Aarhus University Hospital; Henning Danielsen, Department of Internal Medicine, Region Hospital Viborg; Jens Juul, Department of Internal Medicine, Region Hospital Herning; Jørn S. Rasmussen, Department of Surgery, Region Hospital Horsens; Lars Østergaard, Department of Infectious Medicine, Aarhus University Hospital; Lene S. Mortensen, Department of Internal Medicine, Region Hospital Randers; Lene Rosendahl, Department of Neurology, Region Hospital Viborg; Niels Hald, Department of Surgery, Region Hospital Herning; Niels Uldbjerg, Department of Gynecology and Obstetrics, Aarhus University Hospital; Peder Graversen, Department of Urology, Region Hospital Holstebro; Per Kjærsgaard, Department of Pediatrics, Region Hospital Herning; Per Sidenius, Department of Neurology, Aarhus University Hospital; Pernille Sarto, Emergency Department, Region Hospital Horsens; Peter Toft, Center of Planned Surgery, Region Hospital Silkeborg; Rune Weis Næraa, Department of Pediatrics, Aarhus University Hospital; Steen Elkjær Husted, Department of Internal Medicine, Hospital Unit West; Steen Olesen, Department of Orthopedic Surgery, Region Hospital Viborg; Sten Larsen, Department of Orthopedic Surgery, Aarhus University Hospital; Stinne Kvist, Department of Nephrology, Aarhus University Hospital; Thomas Hahn, Department of Internal Medicine, Region Hospital Horsens; Toke Bek, Department of Ophthalmology, Aarhus University Hospital; Ulrich Fredberg, Center of Diagnostics, Region Hospital Silkeborg. The authors thank the data manager, Michael Mogensen, from the Hospital Pharmacy at Aarhus University Hospital, for identifying patients from the study population receiving hormone replacement.

Disclosure

The authors report no conflicts of interest in this work.