Follow-up examination after three years
Three years after inclusion, the patients and their next of kin, if any, as well as healthcare workers from nursing homes or home-based care wherever relevant, were contacted in telephone surveys administered from Innlandet Hospital, Sanderud. In the interviews we collected information on the course of depression, cognition, physical health (GMHR) and functioning (Lawton and Brody's scale for I-ADL). If there were discrepancies between the information provided by the patient and the next of kin/healthcare workers, the interviewers would make a discretionary decision regarding what information should be deemed most valid. The patients were asked to describe their experience of the course of depression (cured of depression / relapse of depression / persistently ill from depression) after the one-year follow-up. They were interviewed with a validated telephone version of the MADRS (17) (n = 105). In addition, the next of kin and/or healthcare workers completed the Cornell scale for depression in dementia (n = 106).
The patients (n = 95) went through a validated telephone version of the Mini Mental State Examination (MMSE) (18). Eighteen further patients whose health condition precluded implementation of the test by telephone went through a traditional MMSE test (14) in the primary health service. Cognitive change over time was measured by the Informant Questionnaire on Cognitive Decline in the Elderly (19), and the Clinical Dementia Rating (20) was completed by the interviewer based on all information on cognition derived from the telephone interviews. The Informant Questionnaire on Cognitive Decline in the Elderly contains 16 questions on cognitive changes over time, for the purposes of this study over the last two years. The Clinical Dementia Rating is used to evaluate cognition and functioning based on available information on memory, orientation, judgement and problem solving, community affairs, home and hobbies, and personal care.
Based on the data that the study had collected on depression at the one-year and three-year follow-up surveys, we classified the course of depression over three years in the categories favourable/less favourable/unfavourable/unclassifiable. The category unfavourable course included patients who had attempted suicide, suffered at least one relapse that required hospitalisation or were assessed by the interviewer as persistently ill from a depressive condition. The less favourable category included patients who had shown symptoms of depression (MADRS > 9 (21) and/or CSDD > 8 (22)), but did not fulfil the criteria for a favourable or unfavourable course. A favourable course meant that the patients had not suffered a relapse of depression or depressive symptoms (MADRS > 9 and/or CSDD > 8) in the follow-up period.
Three of the authors, all psychiatrists with a PhD degree, used all available information from the surveys to independently classify cognition in the three-year survey into the categories no cognitive impairment, mild cognitive impairment according to the Winblad criteria (23), and dementia according to ICD-10 (11). The three experts were in initial agreement on the classification of the cognitive status of 102 out of 131 patients (77.9 %), and held a consensus meeting to classify those 29 patients (22.1 %) for whom there was no correspondence.