Flemming Mørkeberg Nilsson

Increased risk of developing dementia in patients with major affective disorders compared to patients with other medical illnesses

BACKGROUND The association between affective disorder and subsequent dementia is unclear. Our aim was to investigate whether patients with unipolar or bipolar affective disorder have an increased risk of developing dementia compared to patients with other chronic illnesses. METHOD By linkage of the psychiatric and somatic nation-wide registers of all hospitalised patients in Denmark, 2007 patients with mania, 11741 patients with depression, 81380 patients with osteoarthritis and 69149 patients with diabetes were identified according to diagnosis at first-ever discharge from a psychiatric or somatic hospital between 1 January 1977 and 31 December 1993. The risk of receiving a diagnosis of dementia on subsequent re-admission was estimated with the use of survival analyses. RESULTS Patients with unipolar or bipolar affective disorder had a greater risk of receiving a diagnosis of dementia than patients with osteoarthritis or diabetes. Differences in age and gender and the effect of alcohol- or drug-abuse did not explain these associations. CONCLUSION Patients with unipolar or bipolar affective disorder seem to have an increased risk of developing dementia compared to patients with other illnesses. LIMITATION The study includes only patients who have been hospitalised at least once. CLINICAL RELEVANCE Patients with unipolar or bipolar affective disorder may be at increased risk of developing dementia.

Increased risk of developing Parkinson's disease for patients with major affective disorder: a register study

Objective:  To investigate whether patients with a diagnosis of affective disorder are at an increased risk of developing Parkinsons disease compared with medically ill control groups.

Major depressive disorder in Parkinson's disease: a register-based study.

Nilsson FM, Kessing LV, Sørensen TM, Andersen PK, Bolwig TG. Major depressive disorder in Parkinsons disease: a register‐based study. Acta Psychiatr Scand 2002: 106: 202–211.

Increased risk of developing stroke for patients with major affective disorder--a registry study.

Only a few studies have evaluated depressive disorder as a risk factor for cerebrovascular disease. In a hospital discharge register with nation–wide coverage of all hospitals in Denmark we used linkage between the somatic and psychiatric registries to study comorbidity between affective disorders and cerebrovascular diseases in hospitalised patients. The main finding of this study was that patients with depression severe enough to be hospitalised, seem to be at an increased risk of developing cerebrovascular disease. The hazard ratio of getting a diagnosis of stroke after initially having been discharged with a diagnosis of depression was found to be 1.22 (95% Confidence Interval: 1.06–1.41). In the group of patients with manic/bipolar disorder no association was found concerning development of stroke. In elderly with first time depression admitted to hospital, neurological disorders should be carefully evaluated and especially the risk of stroke should be considered.

Enduring increased risk of developing depression and mania in patients with dementia

Objective: To investigate the time relation between dementia and major affective disorders (major depression and mania). Methods: Register linkage study of the Danish Hospital Register and the Danish Psychiatric Central Research Register, to establish study cohorts of patients with dementia and control groups (osteoarthritis or diabetes) on first discharge from hospital. Follow up of cohorts was for up to 21 years. Hazard of death was allowed for by the use of competing risks models. Results: Patients with dementia had an increased risk of being admitted to hospital for major depression or mania during the course of the illness. The incidence remained elevated throughout the rest of the patients life. Conclusions: Patients with dementia have an increased risk of developing depression or mania. Proper treatment of affective disorders in patients with dementia is important in reducing suffering and costs.

No increased risk of developing depression in diabetes compared to other chronic illness

Several studies have found that the prevalence of depression in patients with diabetes is higher than in the general population but it is unclear whether patients with diabetes have an increased risk of developing depression compared with patients with other chronic illnesses. In a nationwide case register study, all patients who had a discharge diagnosis of diabetes or of osteoarthritis at first admission in a period from 1977 to 1997 were identified. The probability of being readmitted and discharged with a diagnosis of depression was estimated with competing risks models in survival analysis. In total, 91,507 patients with a diagnosis of diabetes at first discharge and 108,487 patients with a diagnosis of osteoarthritis were identified. The median age of the populations was high. No difference in the risk of being readmitted with a diagnosis of depression was found between the two groups of patients. There was no difference in the risk for Type 1 and Type 2 diabetes. It is concluded that older patients with diabetes do not seem to have an increased risk of developing severe depression compared with patients with other chronic illness.

On the increased risk of developing late-onset epilepsy for patients with major affective disorder.

BACKGROUND Based on register data we wanted to investigate whether patients with a diagnosis of affective disorder are at increased risk of developing epilepsy compared to other medically ill control groups. METHODS By linkage of public hospital registers covering the whole of Denmark from 1977 to 1993, using ICD-8 diagnoses, three study cohorts were identified: Patients with first affective disorder episodes (mania and depression), patients with first osteoarthritis and patients with first diabetes discharge. Time to first diagnosis of epilepsy was estimated with the use of survival analysis. RESULTS A total of 164,227 patients entered the study base: 13,748 patients with mania or depression, 81,380 patients with osteoarthritis and 69,149 patients with diabetes. The risk of getting a diagnosis of epilepsy was increased for patients with affective disorder compared with the risk for the control groups. However, the increased risk seemed to be due to the effect of comorbid alcohol or drug abuse and not to the effect of the affective illness itself. LIMITATIONS The results only apply to hospitalised patients. Diagnoses are not validated for research purposes. CONCLUSION Patients with a diagnosis of affective disorder have an increased risk of developing epilepsy in later life. In patients with affective disorder, comorbid alcoholism/drug abuse seriously increased the risk of a subsequent diagnosis of epilepsy.

Treatment with antidepressants and lithium is associated with increased risk of treatment with antiparkinson drugs: a pharmacoepidemiological study

Objective: To estimate the risk for persons treated with antidepressants or lithium of subsequent treatment with antiparkinson drugs (APD). Methods: The Danish national prescription database supplied data on all persons who received antidepressants, lithium, or antidiabetics (first control group). A second control group was included comprising persons from the general population. Outcome was purchase of APD and the study period was 1995 to 1999. Results: In total, 1 293 789 persons were included. The rate ratio of treatment with APD after treatment with antidepressants was 2.27 (95% CI 2.14 to 2.42) for men and 1.50 (95% CI 1.43 to 1.58) for women. Figures for lithium were almost identical. Conclusion: Persons treated with antidepressants or lithium are at increased risk of subsequently treatment with APD, showing an association between anxiety/affective disorder and Parkinson’s disease.

Use of antiparkinsonian drugs in Denmark: Results from a nationwide pharmacoepidemiological study

The objective of the present study was to record the use of antiparkinsonian drugs (APD) in Denmark and discuss estimates of the incidence and prevalence rates of Parkinsons disease (PD). The main indication for treatment with APD is idiopathic PD. The use of APD is, therefore, an indicator of the epidemiology of PD and Parkinsonism. We used a drug tracer design, which previously has been found applicable in estimating the frequency of PD. From a national prescription database, all persons who purchased APD from 1995 to 2002 could be identified on an individual level. Results show an age‐standardized prevalence rate for APD purchase of 164.0 persons per 100,000, and an incidence rate of 55.9 persons per 100,000. The total number of persons purchasing APD was 11,656 per year on average. Our results showed higher figures of persons purchasing APD than the estimated prevalence of idiopathic PD in Denmark, which is approximately 100 persons per 100,000, corresponding to 5,000 to 6,000 persons. The differences might in part be explained by other indications for APD prescription in addition to PD and in part by misdiagnosis. However, the possibility of somewhat higher incidence and prevalence rates of PD than hitherto estimated should be considered.

Treatment with antiparkinson and antidepressant drugs: A register‐based, pharmaco‐epidemiological study

Depressive symptoms and major depression are frequent in patients with Parkinsons disease (PD). However, a systematic knowledge about the treatment with antidepressant drugs among PD patients is missing. We estimated the frequency of antidepressant drug treatment in a national sample of persons treated with antiparkinson drugs (APDs). All persons treated with APDs were identified in the national Danish Prescription database. The subsequent risk of treatment with antidepressants was estimated and compared with the risks for two large control groups. The study period was 5 years. In total, 1,029,737 persons were included. Persons who got APDs had significantly increased rate ratios (RR) of subsequent antidepressant drug treatment compared with an unexposed control group (RR: 2.10 (95% CI: 2.04–2.16)) and with persons who got anti‐diabetic drugs [RR: 1.58 (95% CI: 1.51–1.65)]. Persons treated with APDs have higher frequency of antidepressant drug treatment than have controls. With the reservation that data on drug consumption cannot be directly transferred into conclusions about specific diseases, the present study supports results from other population‐based studies of an association between PD and depression.