Cannabis and depression: A twin model approach to co-morbidity

Cannabis use disorder (CUD) co-occurs with major depressive disorder (MDD) more frequently than would be expected by chance. However, studies to date have not produced a clear understanding of the mechanisms underlying this co-morbidity. Genetically informative studies can add valuable insight to this problem, as they allow the evaluation of competing models of co-morbidity. This study uses data from the Australian Twin Registry to compare 13 co-morbidity twin models initially proposed by Neale and Kendler (Am J Hum Genet 57:935–953, 1995). The analysis sample comprised 2410 male and female monozygotic and dizygotic twins (average age 32) who were assessed on CUD and MDD using the SSAGA-OZ interview. Data were analyzed in OpenMx. Of the 13 different co-morbidity models, two fit equally well: CUD causes MDD and Random Multiformity of CUD. Both fit substantially better than the Correlated Liabilities model. Although the current study cannot differentiate between them statistically, these models, in combination, suggest that CUD risk factors may causally influence the risk to develop MDD, but only when risk for CUD is high

Comorbidities only account for a small proportion of excess mortality after fracture: A record linkage study of individual fracture types

Background: Non-hip non-vertebral fractures (NHNV) constitute the majority of osteoporotic fractures but few studies have examined the association between these fractures, co-morbidity and mortality. Objective: To examine the relationship between individual non-hip non-vertebral fractures, co-morbidities and mortality. Methods: Prospective population-based cohort of 267,043 subjects (45 and Up Study, Australia) had baseline questionnaires linked to hospital administrative and all-cause mortality data from 2006 - 2013. Associations between fracture and mortality examined using multivariate, time dependent Cox models, adjusted for age, prior fracture, body mass index, smoking and co-morbidities (cardiovascular disease, diabetes, stroke, thrombosis and cancer) and survival function curves. Population attributable fraction calculated for each level of risk exposure. Results: During 1,490,651 person-years, women and men experienced 7,571 and 4,571 fractures and 7,064 deaths and 11,078 deaths, respectively. In addition to hip and vertebral fractures, pelvis, humerus, clavicle, rib, proximal tibia/fibula, elbow and distal forearm fractures in both sexes, and ankle fractures in men, were associated with increased multivariable adjusted mortality hazard ratios ranging from 1.3 to 3.4. Co-morbidity independently added to mortality such that a woman with a humeral fracture and one co-morbidity had a similarly reduced 5 year survival to that of a woman with a hip fracture and no co-morbidities. Population mortality attributable to any fracture without co-morbidity was 9.2% in women and 5.3% in men. Conclusion: All proximal non-hip, non-vertebral fractures in women and men were associated with increased mortality risk. Co-existent co-morbidities independently further increased mortality. Population attributable risk for mortality for fracture was similar to cardiovascular disease and diabetes, highlighting their importance and potential benefit for early intervention and treatment

Evaluation of the burden of unsuspected pulmonary tuberculosis and co-morbidity with non-communicable diseases in sputum producing adult inpatients

A high burden of tuberculosis (TB) occurs in sub-Saharan African countries and many cases of active TB and drug-resistant TB remain undiagnosed. Tertiary care hospitals provide an opportunity to study TB co-morbidity with non-communicable and other communicable diseases (NCDs/CDs). We evaluated the burden of undiagnosed pulmonary TB and multi-drug resistant TB in adult inpatients, regardless of their primary admission diagnosis, in a tertiary referral centre. In this prospective study, newly admitted adult inpatients able to produce sputum at the University Teaching Hospital, Lusaka, Zambia, were screened for pulmonary TB using fluorescent smear microscopy and automated liquid culture. The burden of pulmonary TB, unsuspected TB, TB co-morbidity with NCDs and CDs was determined. Sputum was analysed from 900 inpatients (70.6% HIV infected) 277 (30.8%) non-TB suspects, 286 (31.8%) TB suspects and 337 (37.4%) were already receiving TB treatment. 202/900 (22.4%) of patients had culture confirmed TB. TB co-morbidity was detected in 20/275 (7.3%) NCD patients, significantly associated with diabetes (P = 0.006, OR 6.571, 95%CI: 1.706-25.3). 27/202 (13.4%) TB cases were unsuspected. There were 18 confirmed cases of MDR-TB, 5 of which were unsuspected. A large burden of unsuspected pulmonary TB co-morbidity exists in inpatients with NCDs and other CDs. Pro-active sputum screening of all inpatients in tertiary referral centres in high TB endemic countries is recommended. The scale of the problem of undiagnosed MDR-TB in inpatients requires further study

The Role of Diabetes Co-Morbidity for Tuberculosis Treatment Outcomes: A Prospective Cohort Study from Mwanza, Tanzania.

Due to the association between diabetes and pulmonary tuberculosis (TB), diabetes may threaten the control of TB. In a prospective cohort study nested in a nutrition trial, we investigated the role of diabetes on changes in anthropometry, grip strength, and clinical parameters over a five months follow-up period. Among pulmonary TB patients with known diabetes status, we assessed anthropometry and clinical parameters (e.g. haemoglobin) at baseline and after two and five months of TB treatment. A linear mixed-effects model (repeated measurements) was used to investigate the role of diabetes during recovery. Of 1205 TB patients, the mean (standard deviation) age was 36.6 (13.0) years, 40.9% were females, 48.9% were HIV co-infected, and 16.3% had diabetes. TB patients with diabetes co-morbidity experienced a lower weight gain at two (1.3 kg, CI95% 0.5; 2.0, p = 0.001) and five months (1.0 kg, CI95% 0.3; 1.7, p = 0.007). Similarly, the increase in the level of haemoglobin was lower among TB patients with diabetes co-morbidity after two (Δ 0.6 g/dL, CI95% 0.3; 0.9 p < 0.001) and five months (Δ 0.5 g/dL, CI95% 0.2; 0.9 p = 0.004) of TB treatment, respectively. TB patients initiating TB treatment with diabetes co-morbidity experience delayed recovery of body mass and haemoglobin, which are important for the functional recovery from disease

Co-infections with Plasmodium falciparum, Schistosoma mansoni and intestinal helminths among schoolchildren in endemic areas of northwestern Tanzania.

Malaria, schistosomiasis and intestinal helminth infections are causes of high morbidity in most tropical parts of the world. Even though these infections often co-exist, most studies focus on individual diseases. In the present study, we investigated the prevalence of Plasmodium falciparum-malaria, intestinal schistosomiasis, soil-transmitted helminth infections, and the respective co-infections, among schoolchildren in northwest Tanzania. A cross sectional study was conducted among schoolchildren living in villages located close to the shores of Lake Victoria. The Kato Katz technique was employed to screen faecal samples for S. mansoni and soil-transmitted helminth eggs. Giemsa stained thick and thin blood smears were analysed for the presence of malaria parasites. Of the 400 children included in the study, 218 (54.5%) were infected with a single parasite species, 116 (29%) with two or more species, and 66 (16.5%) had no infection. The prevalences of P. falciparum and S. mansoni were 13.5% (95% CI, 10.2-16.8), and 64.3% (95% CI, 59.6-68.9) respectively. Prevalence of hookworm infection was 38% (95% CI, 33.2-42.8). A. lumbricoides and T. trichiura were not detected. Of the children 26.5% (95% CI, 21.9-30.6) that harbored two parasite species, combination of S. mansoni and hookworm co-infections was the most common (69%). Prevalence of S. mansoni - P. falciparum co-infections was 22.6% (95%CI, 15.3-31.3) and that of hookworm - P. falciparum co-infections 5.7% (95%CI, 2.6-12.8). Prevalence of co-infection of P. falciparum, S. mansoni and hookworm was 2.8% (95%CI, 1.15-4.4). Multiple parasitic infections are common among schoolchildren in rural northwest Tanzania. These findings can be used for the design and implementation of sound intervention strategies to mitigate morbidity and co-morbidity

Challenges for co-morbid chronic illness care and policy in Australia: a qualitative study

BACKGROUND: In response to the escalating burden of chronic illness in Australia, recent health policies have emphasised the promotion of patient self-management and better preventive care. A notable omission from these policies is the acknowledgment that patients with chronic illness tend to have co-morbid conditions. Our objectives were: to identify the common challenges co-morbidity poses to patients and carers in their experiences of self-management; to detail the views and perceptions of health professionals about these challenges; and to discuss policy options to improve health care for people with co-morbid chronic illness. The method included semistructured interviews and focus groups with 129 purposively sampled participants. Participants were people with Type 2 diabetes, chronic obstructive pulmonary disease and/or chronic heart failure as well as carers and health care professionals. Content analysis of the interview data was conducted using NVivo7 software. RESULTS: Patients and their carers found co-morbidity influenced their capacity to manage chronic illness in three ways. First, co-morbidity created barriers to patients acting on risk factors; second, it complicated the process of recognising the early symptoms of deterioration of each condition, and third, it complicated their capacity to manage medication. CONCLUSION: Findings highlight challenges that patients with multiple chronic conditions face in relation to preventive care and self-management. Future clinical policy initiatives need to move away from single illness orientation toward strategies that meet the needs of people with co-morbid conditions and strengthen their capacity to self-manage. These patients will benefit directly from specialised education and services that cater to the needs of people with clusters of co-morbidities.NHMRC, Australian National University, University of Sydney, Menzies Centre for Health Polic

Prevalence of co-morbidity and its relationship to treatment among unselected patients with Hodgkin's disease and non Hodgkin's lymphoma, 1993-l996

A population-based series of patients with cancer is likely to comprise more patients with serious co-morbidity than clinical trials because of restrictive eligibility criteria for the latter. Since co-morbidity may influence decision-making, we studied the age-specific prevalence of co-morbidity and its relationship to applied treatment. Data on all 194 patients with Hodgkin's disease (HD) and on 904 patients with non-Hodgkin's lymphoma (NHL) diagnosed between 1993 and 1996 were derived from the Eindhoven Cancer Registry. In the age-group below 60 years, 87% of patients with HD and 80% with NHL did not have a co-morbid condition. The prevalence of serious co-morbidity was 56% for patients with Hodgkin's disease who were 60 years and over and 43% and 61% for non Hodgkin patients who were 60-69 years and 70 years and over, respectively. The most common co-morbid conditions were cardiovascular disease (18%), hypertension (13%), chronic obstructive pulmonary disease (COPD; 13%), and diabetes mellitus (10%) for elderly Hodg kin's patients. For non-Hodgkin's patients of 60-69 years and 70 years and over, cardiovascular disease (15 and 22%, respectively), hypertension (14 and 14%, respectively), COPD (6 and 10% respectively), and diabetes mellitus (8 and 10% respectively) were the most prevalent co-morbid conditions. The presence of co-morbidity was not related to stage or grade of disease at diagnosis. In the presence of co-morbidity, 50% less chemotherapy was administered to elderly patients with Hodgkin's disease and 10-15% less to elderly patients with non-Hodgkin's lymphoma. The presence of co-morbidity was associated with a decreased overall survival within the first 4 months after diagnosis in both Hodgkin's disease and non-Hodgkin's lymphoma for all age-groups. In conclusion, serious co-morbidity was found for more than half of all lymphoma patients who were 60 years and older. Elderly patients with serious co-morbidity received chemotherapy less often, which is likely to affect survival adversely, as was indicated by a decreased survival within the first 4 months after diagnosis

Data enhancement for co-morbidity measurement among patients referred for sleep diagnostic testing: an observational study

<p>Abstract</p> <p>Background</p> <p>Observational outcome studies of patients with obstructive sleep apnea (OSA) require adjustment for co-morbidity to produce valid results. The aim of this study was to evaluate whether the combination of administrative data and self-reported data provided a more complete estimate of co-morbidity among patients referred for sleep diagnostic testing.</p> <p>Methods</p> <p>A retrospective observational study of 2149 patients referred for sleep diagnostic testing in Calgary, Canada. Self-reported co-morbidity was obtained with a questionnaire; administrative data and validated algorithms (when available) were also used to define the presence of these co-morbid conditions within a two-year period prior to sleep testing.</p> <p>Results</p> <p>Patient self-report of co-morbid conditions had varying levels of agreement with those derived from administrative data, ranging from substantial agreement for diabetes (κ = 0.79) to poor agreement for cardiac arrhythmia (κ = 0.14). The enhanced measure of co-morbidity using either self-report or administrative data had face validity, and provided clinically meaningful trends in the prevalence of co-morbidity among this population.</p> <p>Conclusion</p> <p>An enhanced measure of co-morbidity using self-report and administrative data can provide a more complete measure of the co-morbidity among patients with OSA when agreement between the two sources is poor. This methodology will aid in the adjustment of these coexisting conditions in observational studies in this area.</p

Posttraumatic stress disorder and psychiatric co-morbidity following stroke: The role of alexithymia

More research is needed to further our understanding of posttraumatic stress disorder symptoms (PTSD) and psychiatric co-morbidity following stroke, especially the trajectories of such symptoms over time. Previous studies suggest that exposure to a traumatic experience such as stroke is not sufficient to explain the etiology of PTSD. Alexithymia may be involved, but its relationships with PTSD and psychiatric co-morbidity following stroke remains unclear. This study aims to address these knowledge gaps. While in hospital, stroke patients (n = 90) completed questionnaires assessing PTSD symptoms, psychiatric co-morbidity, alexithymia and physical disability. PTSD symptoms and psychiatric co-morbidity were re-assessed approximately 3. months post-stroke (n = 78). The severity of post-stroke PTSD did not change significantly over time, while psychiatric co-morbidity reduced significantly. Alexithymia, in particular difficulty in identifying feelings, was associated with severity of post-stroke PTSD and psychiatric co-morbidity at baseline, but after adjusting for these, there was no significance 3. months post-stroke. We suggest that patients\u27 difficulty in identifying feelings had a role to play in influencing relatively short-term rather than long-term PTSD and co-morbid psychiatric symptoms. Alternatively, PTSD could be interpreted as driving the alexithymic characteristics. © 2010 Elsevier Ltd