Concurrent Validity of the Hamilton Depression Rating Scale and the Beck Depression Inventory versus the ICD-10 Diagnostic Criteria among Patients with Parkinson's Disease

Objective: To examine the concurrent validity of the Hamilton Depression Rating Scale and the Beck Depression Inventory for quantifying depression in patients with Parkinson’s disease, using the ICD-10 Diagnostic Criteria as the gold standard, and to determine if the somatization items considered are pertinent. Methods: The study involved one hundred and forty consecutive PD patients –102 men and 38 women– with a mean age of 68.7 years and mean disease duration of 6.7 years. Sensitivity, specificity, positive and negative predictive values and likelihood ratios were obtained with a 95% CI. ROC Curves (AUC) were also performed. Results: Based on ROC measurement of discriminative ability, our results suggest that both scales were poor at recognizing mild depression, somewhat better at recognizing moderate depression and adequate for distinguishing severe depression, though with poor specific ity. Comparisons of HDRS-21, HDRS-12, BDI-21 and BDI-16 to determine concurrent validity all gave similar results for each depression level and no important differences between the complete scales (all 21 items) and abbreviated forms (without somatic items) were noted. Conclusions: We conclude that both scales possess similar psychometric properties, but our results cannot be compared with those of other studies that used DSM-IV criteria as their gold standard. These observations led to the following conclusions: (1) the evaluation scales and criteria that comprise them were not designed for PD; (2) the somatic items observed in our patients were a product of PD; and (3) as the severity of the illness increased, so did the number of items that were confused as elements of depression. Key points: (i)Depression, (ii)Parkinson’s disease, (iii)Hamilton Depression Rating Scale, (iv)Beck Depression Inventory, (v)Somatic items in depression, (vi)Sensitiviy, (vii)Specificity. Abbreviations: PD: Parkinson’s disease UKPDSBB: Kingdom PD Society Brain Bank criteria ADL: Activities of Daily Living HY: Hoehn and Yahr scale. The HY scale is universally used as a severity indicator, both in clinical practice and research, and for selection of patients to be included in clinical trials. It is made up of 6 points of increasing progression (from 0, No signs of disease, to 5, Wheelchair bound or bedridden unless aided) SES: Schwab and England scale. SES scores are expressed in terms of percentage, in 11 steps from 100 to 0, where 100% denotes complete independence and 0% denotes bedridden with vegetative dysfunction SPMSQ: Pfeiffer’s Short Portable Mental Status Questionnaire. The SPMSQ is a 10-item scale rated by interview, and is used to detect and estimate the severity of cognitive impairment. It explores memory (short- and long-term), orientation (time, place and self), and basic calculations. The SPMSQ is hardly influenced by educational level and, as a result, proves quite useful and reliable for scree ning general and elderly populations. Five errors or more are indicative of moderate or severe impairment. UPDRS: Unified Parkinson’s Disease Rating Scale. The UPDRS, officially known as UPDRS version 3.0, is the most widelyapplied clinical rating scale for PD and a gold standard reference scale. UPDRS consists of the following 4 subscales: 1) Part I (4 items; scoring: 0-16 points), mentation, behaviour and mood; 2) Part II (13 items; 0-52 points), activities of daily living (ADL), which may be scored in “on” or “off” states; 3) Part III (14 items; 0-108 points), motor examination (this section produces 27 scores due to assessment of several signs in different parts of the body); and 4) Part IV (11 items; 23 points–not applied in the present study –), assessing for dyskinesias, fluctuations and other complications. Items belonging to the sections I to III score from 0 (normal) to 4 (severe), whereas scoring of the part IV is heterogeneous.