Preliminary data of a HAMD-17 validated symptom scale derived from the ICD-10 to diagnose depression in outpatients

In outpatient settings diagnostic classification of depressive symptoms is mostly descriptive based on ICD-10. Depending on clinical experience and consultation time, diagnosis can be verified by validated scales. However, physicians working in primary care are familiar with ICD-10 criteria. Therefore, the aim of the present study was to examine the feasibility of the validation of an ICD-10-derived symptom scale for depression.

For this preliminary trial we generated a symptom scale derived 1:1 from the diagnostic criteria for depression given in the ICD-10 with 10 items. The Hamilton Rating Scale for Depression (HAMD-17) was used as reference in a population of 226 outpatients suffering from depressive symptoms. Correlation between scales as well as sensitivity and specificity of the ICD-10 scale were calculated.

The generated ICD-10 symptom scale for depression could be analyzed in 219 patients and showed a significant and strong correlation with the HAMD-17 (p < 0.0001; ρ = 0.75). The best tradeoffs between specificity and sensitivity of the ICD-10 score were found at 10 points for the lower and 14 points for the upper cut-off. Overall sensitivity and specificity was 76.7 and 88.6%. Almost two thirds (i.e. 65.3%) of the patients were correctly classified by the ICD-10 scale.

The ICD-10 symptom scale examined in the current population was found to have fair correlation with the HAMD-17 as well as, in face of the limited variance of the patients' condition, acceptable sensitivity and specificity. Therefore, this preliminary study showed that the ICD-10-derived symptom scale seems appropriate to be investigated in a thorough validation trial.