Downloaded from http://jnnp.bmj.com/ on November 23, 2014 - Published by group.bmj.com
Cerebrovascular disease
RESEARCH PAPER
The long-term outcomes of depression up to 10 years after stroke; the South London Stroke Register L Ayerbe,1,2 S Ayis,1 S Crichton,1 C D A Wolfe,1,3 A G Rudd1,4 1
Division of Health and Social Care Research, King’s College London, London, UK 2 Blizard Institute, Centre for Primary Care and Public Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK 3 National Institute for Health Research (NIHR) Biomedical Research Centre, Guy’s and St Thomas’ NHS Foundation Trust, London, UK 4 Stroke Unit, Guy’s and St. Thomas’ NHS Foundation Trust, St. Thomas’ Hospital London, London, UK Correspondence to Dr Luis Ayerbe, Blizard Institute, Centre for Primary Care and Public Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Yvonne Carter Building, 58 Turner Street, London E1 2AB, UK; [email protected] Received 31 July 2013 Revised 30 September 2013 Accepted 7 October 2013 Published Online First 25 October 2013
ABSTRACT Background Post-stroke depression is a frequent chronic and recurrent problem that starts shortly after stroke and affects patients in the long term. The health outcomes of depression after stroke are unclear. Aims (1) To investigate the associations between depression at 3 months and mortality, stroke recurrence, disability, cognitive impairment, anxiety and quality of life (QoL), up to 5 years post-stroke. (2) To investigate these associations in patients recovering from depression by year 1. (3) To investigate associations between depression at 5 years and these outcomes up to 10 years. Methods Data from the South London Stroke Register (1997–2010) were used. Patients (n at registration=3240) were assessed at stroke onset, 3 months after stroke and annually thereafter. Baseline data included sociodemographics and stroke severity measures. Follow-up assessments included anxiety and depression (Hospital Anxiety and Depression scale), disability, QoL and stroke recurrence. Multivariable regression models adjusted for age, gender, ethnicity, stroke severity and disability were used to investigate the association between depression and outcomes at follow-up. Results Depression at 3 months was associated with: increased mortality (HR: 1.27 (1.04 to 1.55)), disability (RRs up to 4.71 (2.96 to 7.48)), anxiety (ORs up to 3.49 (1.71 to 7.12)) and lower QoL (coefficients up to −8.16 (−10.23−6.15)) up to year 5. Recovery from depression by 1 year did not alter these risks to 5 years. Depression in year 5 was associated with anxiety (ORs up to 4.06 (1.92 to 8.58)) and QoL (coefficients up to −11.36 (−14.86 to −7.85)) up to year 10. Conclusions Depression is independently associated with poor health outcomes.
INTRODUCTION
To cite: Ayerbe L, Ayis S, Crichton S, et al. J Neurol Neurosurg Psychiatry 2014;85:514–521. 514
Depression after stroke is a common, chronic and recurrent problem affecting patients in the long term.1–5 However, in order to understand the burden of depression in stroke patients, it is also necessary to estimate its potential association with mortality and morbidity over time. A systematic review6 identified studies investigating the association between depression and other health outcomes.2 7–10 Most of these studies had limitations, including small sample size, short follow-up, and poorly reported methods. Although the evidence suggests that depression is associated with higher risk of stroke,11 cognitive impairment12 and anxiety,13 to the best of our knowledge, no studies have investigated the association between
depression and these outcomes at follow-up.6 The association of depression with other health outcomes could change in patients who recover from depression. However, the effect of recovery has not been investigated in any of the studies.6 Finally, while the long-term outcomes of depression may be affected by episodes of depression occurring more than 1 year after stroke, no studies investigated depression as an exposure more than 3 months after stroke.6 Therefore, the prognosis and consequences of depression in the long term after stroke remain unclear and this limits its clinical management. This study estimates the association between depression 3 months after stroke and mortality, stroke recurrence, disability, cognitive impairment, anxiety and quality of life (QoL) up to 5 years after stroke. Second, the association between depression and these health outcomes is also estimated in patients who recover from depression within the first year of stroke (depressed at 3 months and not depressed at 1 year). Finally, the association between depression 5 years after stroke (depressed or not in year 5) and the same outcomes up to 10 years is estimated.
METHODS First in a lifetime stroke patients were recruited from the South London Stroke Register (SLSR), a prospective population-based cohort study covering an inner-city population of 271 817.14 Data from patients, registered in the SLSR between June 1997 and December 2009, and followed-up until August 2010, were used. The methodology has been described in detail previously and is summarised below.14 WHO definition of stroke was used.15 Sixteen overlapping referral sources were used to increase completeness of notification. All patients with a suspected diagnosis of stroke were identified by one of the sources of notification and investigated for eligibility of study inclusion. Patients were registered during the acute phase of stroke and then they were followed-up 3 months after stroke, 1 year after stroke and annually, thereafter, for up to 10 years. A study clinician verified the diagnosis of all patients being registered. Data collected at baseline included sociodemographics and stroke severity measures. Demographic data included age, gender and ethnicity (white, black and other ethnicity). Stroke severity measures included Glasgow Coma Scale (GCS), categorised as severe (3–8), moderate (9–12) and mild (13–15), levels of impairment, urinary incontinence and paresis. Disability was also assessed 7–10 days after stroke
Ayerbe L, et al. J Neurol Neurosurg Psychiatry 2014;85:514–521. doi:10.1136/jnnp-2013-306448
Downloaded from http://jnnp.bmj.com/ on November 23, 2014 - Published by group.bmj.com
Cerebrovascular disease Table 1 Baseline characteristics of patients assessed for depression at 3 months Number (%) Age 0–64 >64 Unknown Gender Male Female Unknown Ethnicity White Black Other Unknown Glasgow Coma Score 3–8 9–12 13–15 Unknown Paresis No Yes Unknown Incontinence No Yes Unknown Disability (Barthel Index) Severe (0–14) Mild (15–19) Independent (20) Unknown
393 (35.7) 708 (64.3) 0 595 (54.0) 506 (46.0) 0 773 (70.2) 247 (22.4) 67 (6.1) 14 (1.3) 31 (2.8) 76 (6.9) 963 (87.5) 31 (2.8) 252 (22.9) 687 (62.4) 162 (14.7) 781 (70.9) 284 (25.8) 36 (3.3) 414 201 296 190
(37.6) (18.3) (26.9) (17.3)
using the Barthel Index (BI)16: scores of 0–14 were categorised as severe disability, 15–19 moderate disability and 20 independent. The BI was chosen to measure disability as it has been widely used in clinical settings and research, and it has excellent test-retest (κ w=0.98) and inter-rater reliability (κ w=0.88).16 17 Follow-up was by postal questionnaire or interview, depending on the capacity of the patient to fill in the questionnaire. Patients who could not be followed-up at one time point remained registered and were contacted again for the following assessment. At follow-up, patients were assessed for depression and anxiety, using the Hospital Anxiety and Depression scale (HADS).18 HADS has been validated in stroke patients showing a good performance when it is used in a face-to-face interview, and when it is self-administered19 (optimum performance when HADS subscales scores above 7 are used to identify anxiety and depression: sensitivity 0.82 and specificity 0.74 for depression, and sensitivity 0.78 and specificity 0.74 for anxiety).18 Despite its good performance, HADS is not a diagnostic scale but a screening tool that detects only symptoms of depression and anxiety. However, the terms ‘depression’ and ‘anxiety’ will be used in this paper for succinctness in patients with scores above 7. Patients with HADS scores above 7 at 3 months, presenting scores below 7 at 1 year, were categorised as patients recovering from depression. HADS cannot be answered by proxy, so all information was collected directly from patients. No data on
anxiety or depression could be collected from patients with cognitive or communication impairment if they were considered unable to give valid responses. The exclusion of these patients was based on the clinical judgement of the SLSR field workers. Other data collected at follow-up included measures of disability, cognitive impairment and QoL. Cognitive impairment was assessed with the Mini Mental State examination (MMSE)20 between 1997 and 2001, and the Abbreviated Memory Test (AMT)21 between 2002 and 2010. Patients with MMSE score
Cerebrovascular disease
RESEARCH PAPER
The long-term outcomes of depression up to 10 years after stroke; the South London Stroke Register L Ayerbe,1,2 S Ayis,1 S Crichton,1 C D A Wolfe,1,3 A G Rudd1,4 1
Division of Health and Social Care Research, King’s College London, London, UK 2 Blizard Institute, Centre for Primary Care and Public Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, London, UK 3 National Institute for Health Research (NIHR) Biomedical Research Centre, Guy’s and St Thomas’ NHS Foundation Trust, London, UK 4 Stroke Unit, Guy’s and St. Thomas’ NHS Foundation Trust, St. Thomas’ Hospital London, London, UK Correspondence to Dr Luis Ayerbe, Blizard Institute, Centre for Primary Care and Public Health, Barts and The London School of Medicine and Dentistry, Queen Mary University of London, Yvonne Carter Building, 58 Turner Street, London E1 2AB, UK; [email protected] Received 31 July 2013 Revised 30 September 2013 Accepted 7 October 2013 Published Online First 25 October 2013
ABSTRACT Background Post-stroke depression is a frequent chronic and recurrent problem that starts shortly after stroke and affects patients in the long term. The health outcomes of depression after stroke are unclear. Aims (1) To investigate the associations between depression at 3 months and mortality, stroke recurrence, disability, cognitive impairment, anxiety and quality of life (QoL), up to 5 years post-stroke. (2) To investigate these associations in patients recovering from depression by year 1. (3) To investigate associations between depression at 5 years and these outcomes up to 10 years. Methods Data from the South London Stroke Register (1997–2010) were used. Patients (n at registration=3240) were assessed at stroke onset, 3 months after stroke and annually thereafter. Baseline data included sociodemographics and stroke severity measures. Follow-up assessments included anxiety and depression (Hospital Anxiety and Depression scale), disability, QoL and stroke recurrence. Multivariable regression models adjusted for age, gender, ethnicity, stroke severity and disability were used to investigate the association between depression and outcomes at follow-up. Results Depression at 3 months was associated with: increased mortality (HR: 1.27 (1.04 to 1.55)), disability (RRs up to 4.71 (2.96 to 7.48)), anxiety (ORs up to 3.49 (1.71 to 7.12)) and lower QoL (coefficients up to −8.16 (−10.23−6.15)) up to year 5. Recovery from depression by 1 year did not alter these risks to 5 years. Depression in year 5 was associated with anxiety (ORs up to 4.06 (1.92 to 8.58)) and QoL (coefficients up to −11.36 (−14.86 to −7.85)) up to year 10. Conclusions Depression is independently associated with poor health outcomes.
INTRODUCTION
To cite: Ayerbe L, Ayis S, Crichton S, et al. J Neurol Neurosurg Psychiatry 2014;85:514–521. 514
Depression after stroke is a common, chronic and recurrent problem affecting patients in the long term.1–5 However, in order to understand the burden of depression in stroke patients, it is also necessary to estimate its potential association with mortality and morbidity over time. A systematic review6 identified studies investigating the association between depression and other health outcomes.2 7–10 Most of these studies had limitations, including small sample size, short follow-up, and poorly reported methods. Although the evidence suggests that depression is associated with higher risk of stroke,11 cognitive impairment12 and anxiety,13 to the best of our knowledge, no studies have investigated the association between
depression and these outcomes at follow-up.6 The association of depression with other health outcomes could change in patients who recover from depression. However, the effect of recovery has not been investigated in any of the studies.6 Finally, while the long-term outcomes of depression may be affected by episodes of depression occurring more than 1 year after stroke, no studies investigated depression as an exposure more than 3 months after stroke.6 Therefore, the prognosis and consequences of depression in the long term after stroke remain unclear and this limits its clinical management. This study estimates the association between depression 3 months after stroke and mortality, stroke recurrence, disability, cognitive impairment, anxiety and quality of life (QoL) up to 5 years after stroke. Second, the association between depression and these health outcomes is also estimated in patients who recover from depression within the first year of stroke (depressed at 3 months and not depressed at 1 year). Finally, the association between depression 5 years after stroke (depressed or not in year 5) and the same outcomes up to 10 years is estimated.
METHODS First in a lifetime stroke patients were recruited from the South London Stroke Register (SLSR), a prospective population-based cohort study covering an inner-city population of 271 817.14 Data from patients, registered in the SLSR between June 1997 and December 2009, and followed-up until August 2010, were used. The methodology has been described in detail previously and is summarised below.14 WHO definition of stroke was used.15 Sixteen overlapping referral sources were used to increase completeness of notification. All patients with a suspected diagnosis of stroke were identified by one of the sources of notification and investigated for eligibility of study inclusion. Patients were registered during the acute phase of stroke and then they were followed-up 3 months after stroke, 1 year after stroke and annually, thereafter, for up to 10 years. A study clinician verified the diagnosis of all patients being registered. Data collected at baseline included sociodemographics and stroke severity measures. Demographic data included age, gender and ethnicity (white, black and other ethnicity). Stroke severity measures included Glasgow Coma Scale (GCS), categorised as severe (3–8), moderate (9–12) and mild (13–15), levels of impairment, urinary incontinence and paresis. Disability was also assessed 7–10 days after stroke
Ayerbe L, et al. J Neurol Neurosurg Psychiatry 2014;85:514–521. doi:10.1136/jnnp-2013-306448
Downloaded from http://jnnp.bmj.com/ on November 23, 2014 - Published by group.bmj.com
Cerebrovascular disease Table 1 Baseline characteristics of patients assessed for depression at 3 months Number (%) Age 0–64 >64 Unknown Gender Male Female Unknown Ethnicity White Black Other Unknown Glasgow Coma Score 3–8 9–12 13–15 Unknown Paresis No Yes Unknown Incontinence No Yes Unknown Disability (Barthel Index) Severe (0–14) Mild (15–19) Independent (20) Unknown
393 (35.7) 708 (64.3) 0 595 (54.0) 506 (46.0) 0 773 (70.2) 247 (22.4) 67 (6.1) 14 (1.3) 31 (2.8) 76 (6.9) 963 (87.5) 31 (2.8) 252 (22.9) 687 (62.4) 162 (14.7) 781 (70.9) 284 (25.8) 36 (3.3) 414 201 296 190
(37.6) (18.3) (26.9) (17.3)
using the Barthel Index (BI)16: scores of 0–14 were categorised as severe disability, 15–19 moderate disability and 20 independent. The BI was chosen to measure disability as it has been widely used in clinical settings and research, and it has excellent test-retest (κ w=0.98) and inter-rater reliability (κ w=0.88).16 17 Follow-up was by postal questionnaire or interview, depending on the capacity of the patient to fill in the questionnaire. Patients who could not be followed-up at one time point remained registered and were contacted again for the following assessment. At follow-up, patients were assessed for depression and anxiety, using the Hospital Anxiety and Depression scale (HADS).18 HADS has been validated in stroke patients showing a good performance when it is used in a face-to-face interview, and when it is self-administered19 (optimum performance when HADS subscales scores above 7 are used to identify anxiety and depression: sensitivity 0.82 and specificity 0.74 for depression, and sensitivity 0.78 and specificity 0.74 for anxiety).18 Despite its good performance, HADS is not a diagnostic scale but a screening tool that detects only symptoms of depression and anxiety. However, the terms ‘depression’ and ‘anxiety’ will be used in this paper for succinctness in patients with scores above 7. Patients with HADS scores above 7 at 3 months, presenting scores below 7 at 1 year, were categorised as patients recovering from depression. HADS cannot be answered by proxy, so all information was collected directly from patients. No data on
anxiety or depression could be collected from patients with cognitive or communication impairment if they were considered unable to give valid responses. The exclusion of these patients was based on the clinical judgement of the SLSR field workers. Other data collected at follow-up included measures of disability, cognitive impairment and QoL. Cognitive impairment was assessed with the Mini Mental State examination (MMSE)20 between 1997 and 2001, and the Abbreviated Memory Test (AMT)21 between 2002 and 2010. Patients with MMSE score
