[Use of discharge records to define the oncological diagnoses for outpatient radiotherapy patients]

Outpatient activity recording system has a potential role in clinical practice evaluation. Nevertheless, up to now, its utilisation has been limited by the paucity of its clinical data. This study describes a procedure for identifying the oncological diagnosis in patients receiving radiotherapy at an ambulatory service in the Piedmont Region. The procedure is based on the record linkage between discharge records (SDO) and outpatients records (PA), in order to obtain clinical information from the diagnosis related to possible admissions of the patients.

The study analyzed radiotherapy outpatients records in 2003 related to Piedmont residents and all discharge records in years 2000-2004. The quality of the procedure has been assessed by using the information on the real oncological diagnosis as reported in the outpatients medical records of a random sample of patients.

The record linkage with SDO allows to define an oncological diagnosis for 82% (95% CI 78.5-84.8) of the patients. Agreement between defined diagnosis and the real one is 85.7% (CI 95% 82.2-88.6). The validity of the procedure is affected by the patients' cancer site. The distribution by cancer site of the patients treated with radiotherapy in Piedmont Region obtained with the record linkage procedure is homogeneous to the real distribution of the random sample used for control.

Overall, the record linkage between SDO and radiotherapy PA shows a good performance in defining the oncological diagnosis of the patients receiving radiotherapy at an ambulatory setting. This method allows to increase interest and utility of PA records.