The search for gastrointestinal inflammation in autism: a systematic review and meta-analysis of non-invasive gastrointestinal markers

BACKGROUND

Gastrointestinal symptoms and inflammatory gastrointestinal diseases exist at higher rates in the autistic population. It is not clear however whether autism is associated with elevated gastrointestinal inflammation as studies examining non-invasive faecal biomarkers report conflicting findings. To understand the research landscape and identify gaps, we performed a systematic review and meta-analysis of studies measuring non-invasive markers of gastrointestinal inflammation in autistic and non-autistic samples. Our examination focused on faecal biomarkers as sampling is non-invasive and these markers are a direct reflection of inflammatory processes in the gastrointestinal tract.

METHODS

We extracted data from case-control studies examining faecal markers of gastrointestinal inflammation. We searched PubMed, Embase, Cochrane CENTRAL, CINAHL, PsycINFO, Web of Science Core Collection and Epistemonikos and forward and backwards citations of included studies published up to April 14, 2023 (PROSPERO CRD42022369279).

RESULTS

There were few studies examining faecal markers of gastrointestinal inflammation in the autistic population, and many established markers have not been studied. Meta-analyses of studies examining calprotectin (n = 9) and lactoferrin (n = 3) were carried out. A total of 508 autistic children and adolescents and 397 non-autistic children and adolescents were included in the meta-analysis of calprotectin studies which found no significant group differences (ROM: 1.30 [0.91, 1.86]). Estimated differences in calprotectin were lower in studies with siblings and studies which did not exclude non-autistic controls with gastrointestinal symptoms. A total of 139 autistic participants and 75 non-autistic controls were included in the meta-analysis of lactoferrin studies which found no significant group differences (ROM: 1.27 [0.79, 2.04]).

LIMITATIONS

All studies included in this systematic review and meta-analysis examined children and adolescents. Many studies included non-autistic controls with gastrointestinal symptoms which limit the validity of their findings. The majority of studies of gastrointestinal inflammation focused on children under 12 with few studies including adolescent participants. Most studies that included participants aged four or under did not account for the impact of age on calprotectin levels. Future studies should screen for relevant confounders, include larger samples and explore gastrointestinal inflammation in autistic adolescents and adults.

CONCLUSIONS

There is no evidence to suggest higher levels of gastrointestinal inflammation as measured by calprotectin and lactoferrin are present in autistic children and adolescents at the population level. Preliminary evidence suggests however that higher calprotectin levels may be present in a subset of autistic participants, who may be clinically characterised by more severe gastrointestinal symptoms and higher levels of autistic traits.

Cancer activates microglia to the same extent as chronic stress throughout stress neurocircuitry in a mouse model of breast cancer

The prevalence of stress-related comorbidities is increased approximately 3-fold in cancer patients compared to the general population. There is a scarcity of research focusing on the biological brain changes caused by the cancer due to the assumption that psychological symptoms are solely caused by the stress of a cancer diagnosis. Recent clinical evidence indicates that declines in cognition and increases in mood symptoms occur prior to an individual receiving a cancer diagnosis, suggesting that the cancer itself may play a role in mediating biological brain change. Furthermore, the presence of a tumour may change the brain response to environmental stressors unrelated to a cancer diagnosis. Using a syngeneic, orthotopic mouse model of breast cancer, we compared the impact of mammary tumours and chronic restraint stress on microglial and astrocytic activation throughout stress-relevant neurocircuitry. We also examined whether changes in microglial and astrocytic activation overlapped with changes in chronic neuronal activity. We show that cancer and chronic restraint stress activates microglia to the same magnitude in the same subcortical brain regions, and that this activation correlates with stress coping behaviours. The findings suggest that in some cancer patients, microglia may be activated in brain regions involved in interpreting and responding to psychological distress before they are aware of their diagnosis. In contrast, cancer reduced astrocyte reactivity in two cortical brain regions where there were no clear changes in response to chronic restraint stress. Taken together, it is likely that interventions that aim to improve anxiety and stress in cancer patients by targeting glial responses to cancer would need to be cell-specific; reducing microglial activation and/or stimulating astrocytic activation.

Cross-sectional study of the prevalence, causes and management of hospital-onset diarrhoea

BACKGROUND

The National Health Service in England advises hospitals collect data on hospital-onset diarrhoea (HOD). Contemporaneous data on HOD are lacking.

AIM

To investigate prevalence, aetiology and management of HOD on medical, surgical and elderly-care wards.

METHODS

A cross-sectional study in a volunteer sample of UK hospitals, which collected data on one winter and one summer day in 2016. Patients admitted ≥72 h were screened for HOD (definition: ≥2 episodes of Bristol Stool Type 5-7 the day before the study, with diarrhoea onset >48 h after admission). Data on HOD aetiology and management were collected prospectively.

FINDINGS

Data were collected on 141 wards in 32 hospitals (16 acute, 16 teaching). Point-prevalence of HOD was 4.5% (230/5142 patients; 95% confidence interval (CI) 3.9-5.0%). Teaching hospital HOD prevalence (5.9%, 95% CI 5.1-6.9%) was twice that of acute hospitals (2.8%, 95% CI 2.1-3.5%; odds ratio 2.2, 95% CI 1.7-3.0). At least one potential cause was identified in 222/230 patients (97%): 107 (47%) had a relevant underlying condition, 125 (54%) were taking antimicrobials, and 195 (85%) other medication known to cause diarrhoea. Nine of 75 tested patients were Clostridium difficile toxin positive (4%). Eighty (35%) patients had a documented medical assessment of diarrhoea. Documentation of HOD in medical notes correlated with testing for C. difficile (78% of those tested vs 38% not tested, P<0.001). One-hundred and forty-four (63%) patients were not isolated following diarrhoea onset.

CONCLUSION

HOD is a prevalent symptom affecting thousands of patients across the UK health system each day. Most patients had multiple potential causes of HOD, mainly iatrogenic, but only a third had medical assessment. Most were not tested for C. difficile and were not isolated.

Chasing balance and other recommendations for improving nonparametric propensity score models

In this article, we carefully examine two important implementation issues when estimating propensity scores using generalized boosted models (GBM), a promising machine learning technique. First, we examine which of the following methods for tuning GBM lead to better covariate balance and inferences about causal effects: pursuing covariate balance between the treatment groups or tuning the propensity score model on the basis of a model fit criterion. Second, we examine how well GBM can handle irrelevant covariates that are included in the estimation model. We find that chasing balance rather than model fit when estimating propensity scores yielded better covariate balance and more accurate treatment effect estimates. Additionally, we find that adding irrelevant covariates to GBM increased imbalance and bias in the treatment effects. The findings from this paper have useful implications for other work focused on improving methods for estimating propensity scores.

Contamination of histology biopsy specimen - a potential source of error for surgeons: a case report

Tissue contamination is a common occurrence in pathology, but surgeons are relatively unaware of this. We present the case of a 45-year-old man with Barrett's oesophagus, in which the histology of routine biopsies of an asymptomatic patient, were reported as 'carcinoma in situ'. Further biopsies were taken over a three month period but showed no evidence of malignancy. Tissue contamination or 'cross over' was identified as the likely cause of the abnormal result. This case report highlights the importance of the correlation of the clinical and histopathological findings and tissue contamination should be considered when both of these findings are not consistent.

Biased emotional attention in post-traumatic stress disorder: a help as well as a hindrance?

BACKGROUND

From a cognitive neuroscience perspective, the emotional attentional bias in post-traumatic stress disorder (PTSD) could be conceptualized either as emotional hyper-responsiveness or as reduced priming of task-relevant representations due to dysfunction in 'top-down' regulatory systems. We investigated these possibilities both with respect to threatening and positive stimuli among traumatized individuals with and without PTSD.

METHOD

Twenty-two patients with PTSD, 21 trauma controls and 20 non-traumatized healthy participants were evaluated on two tasks. For one of these tasks, the affective Stroop task (aST), the emotional stimuli act as distracters and interfere with task performance. For the other, the emotional lexical decision task (eLDT), emotional information facilitates task performance.

RESULTS

Compared to trauma controls and healthy participants, patients with PTSD showed increased interference for negative but not positive distracters on the aST and increased emotional facilitation for negative words on the eLDT.

CONCLUSIONS

These findings document that hyper-responsiveness to threat but not to positive stimuli is specific for patients with PTSD.

Impact of psychiatric conditions on health-related quality of life in persons with HIV infection

OBJECTIVE

Little is known about the impact of comorbid psychiatric symptoms in persons with HIV. This study estimates the burden on health-related quality of life associated with comorbid psychiatric conditions in a nationally representative sample of persons with HIV.

METHOD

The authors conducted a multistage sampling of urban and rural areas to produce a national probability sample of persons with HIV receiving medical care in the contiguous United States (N=2,864). Subjects were screened for psychiatric conditions with the short form of the Composite International Diagnostic Interview. Heavy drinking was assessed on the basis of quantity and frequency of drinking. Health-related quality of life was rated with a 28-item instrument adapted from similar measures used in the Medical Outcomes Study.

RESULTS

HIV subjects with a probable mood disorder diagnosis had significantly lower scores on health-related quality of life measures than did those without such symptoms. Diminished health-related quality of life was not associated with heavy drinking, and in drug users it was accounted for by presence of a comorbid mood disorder.

CONCLUSIONS

Optimization of health-related quality of life is particularly important now that HIV is a chronic disease with the prospect of long-term survival. Comorbid psychiatric conditions may serve as markers for impaired functioning and well-being in persons with HIV. Inclusion of sufficient numbers of appropriately trained mental health professionals to identify and treat such conditions may reduce unnecessary utilization of other health services and improve health-related quality of life in persons with HIV infection.

Hardcore drug users claim to be occasional users: drug use frequency underreporting

Self-reports of drug use frequency are central to treatment outcome evaluations, estimates of the prevalence of heavy use, estimates of treatment need, and other questions with direct relevance to drug policies. Nevertheless, surprisingly little is known about the validity of these self-reports. This study examines the accuracy of 701 frequency self-reports made by a sample of methadone maintenance clients. Self-report accuracy is evaluated by comparing rates of positive urinalyses found for each case with rates that would be expected had drug use occurred only as often as reported. Expected rates of positive urinalyses are derived from conservative Monte Carlo models of drug use for each case. This procedure reveals extensive heroin and cocaine use frequency underreporting. After adjusting for frequency underreporting, 51% of 279 cases reporting only occasional heroin use (1-10 days in the past 30), and 22% of the 157 cases reporting occasional cocaine use, are found to be using these drugs with frequencies corresponding to what the Office of National Drug Control Policy defines as 'hardcore use' (more than 10 days in the past 30). Drug use frequency underreporting appears substantial, and might constitute an important threat to the validity of some treatment outcome evaluations, needs assessments and other analyses that rely on drug use frequency self-reports.

Impact of concurrent amiodarone treatment on the tolerability and efficacy of carvedilol in patients with chronic heart failure

OBJECTIVE

To assess the safety and efficacy of carvedilol when administered to heart failure patients already receiving amiodarone.

DESIGN

Retrospective analysis of the clinical outcome of 230 patients treated with carvedilol for chronic heart failure, stratified according to whether they were already receiving amiodarone (amiodarone group, 80 patients) or not (non-amiodarone group, 130 patients) at baseline.

SETTING

Heart failure clinic at a university affiliated public teaching hospital.

MAIN OUTCOME MEASURES

Incidence of adverse events; changes in functional status and echocardiographic dimensions at three months.

RESULTS

Adverse reactions to carvedilol occurred in 33 (41%) of the amiodarone group and 43 (29%) of the non-amiodarone group (p = 0.049). Carvedilol was discontinued in 21 (26%) of the amiodarone group and 37 (25%) of the non-amiodarone group (NS). The clinical outcome at three months did not differ significantly between the two groups; 31 (39%) of the amiodarone group improved their New York Heart Association status, 28 (35%) were unchanged, and 21 (26%) deteriorated compared with 67 (45%), 51 (34%), and 32 (21%), respectively, for the non-amiodarone group (NS). Both groups had highly significant decreases in heart rate and left ventricular end systolic dimension, and a significant increase in left ventricular ejection fraction after three months of carvedilol treatment, with no significant differences between the groups.

CONCLUSIONS

The beneficial effects of carvedilol on left ventricular remodelling, systolic function, and symptomatic status are not affected by concurrent treatment with amiodarone. Adverse reactions necessitating cessation of carvedilol are no more frequent in patients receiving amiodarone.

Racial differences in functional status among elderly U.S. migrants from the South

This study describes patterns of functional status among older blacks and whites by their history of birth in and migration out of the South. We used multivariate regression to analyze data on functional status of US-born non-Hispanic blacks (N = 1868) and whites (N = 13469) age 60 years or above. In general, the functional status of blacks who were born in the South and migrated was similar to that of blacks born outside the South and better than those born in the South who did not migrate. Whites who migrated from the South had functional status similar to those who did not migrate and worse than those born outside of the South. Socioeconomic status did not explain differences by race and migration history. These results differ sharply from mortality studies, which have found a consistent pattern of high mortality among black migrants from the South. Differences among race groups by migration history vary across health measures. Selective migration and selective survival may account for the complex patterns of racial differences in geographic distributions of function and health.

Effect of a large managed care program on emergency department use: results from the CHAMPUS reform initiative evaluation

STUDY OBJECTIVE

To determine the effect of the CHAMPUS Reform Initiative (CRI) on emergency department use and charges, and to ascertain whether any reductions were concentrated among repeat users of the ED, those with less serious ED diagnoses, or those with selected chronic medical conditions.

METHODS

Participants were approximately 1.2 million beneficiaries of the Civilian Health and Medical Program of Uniformed Services (CHAMPUS) residing within either 11 military hospital catchment areas in California and Hawaii ("demonstration areas") or 11 matched control areas in other parts of the United States. Under CRI, participants were offered a choice of the standard CHAMPUS indemnity plan, a Preferred Provider Organization-type plan, or a network-model Health Maintenance Organization plan. Beneficiaries were encouraged to use alternatives to the ED for nonemergency conditions. Visits to civilian EDs during two 12-month periods, before and after institution of CRI, were compared.

RESULTS

Under CRI, the number of CHAMPUS ED visits decreased by approximately 40% relative to the control, and allowed charges fell by almost 50%. Relative reductions in ED use under CRI were seen among both frequent and infrequent users of the ED. ED case-mix severity increased modestly relative to control (+3.5% versus +.9%). ED use among patients with diabetes, hypertension, and asthma fell sharply in the demonstration areas (by 14% to 41%) but rose in control areas (by 4% to 9%).

CONCLUSION

In one of the largest managed care demonstrations ever conducted, a nonintrusive use management program and improved access to outpatient care appeared to reduce ED use, allowed charges, and costs to the government. Reductions in ED use were concentrated to some extent among repeat users and patients with less severe illnesses and were effected without capitation of provider groups or strict gatekeeping requirements.

Chronic conditions that lead to functional limitation in the elderly

BACKGROUND

The role of chronic medical conditions in elderly persons' loss of functional abilities is intuitively important but not well defined. This analysis was designed to identify chronic medical conditions that lead to the development of severe functional limitation.

METHODS

Functionally intact members of a multistage probability sample (n = 6,862) of all noninstitutionalized U.S. civilians age 70 years or older were interviewed in 1984. Based on data from the National Death Index and from follow-up telephone interviews in 1988 with survivors, subjects were classified as functionally intact, functionally limited (unable to perform one or more of seven essential activities), or decreased.

RESULTS

After adjusting for the effects of exercise habits and demographic, socioeconomic, and psychosocial factors, we found that the best predictors of the development of functional limitation were cerebrovascular disease (OR = 2.14; 95% CL = 1.16, 3.98) and arthritis (OR = 1.51; 95% CL = 1.08, 2.11). The contribution of coronary artery disease also approached statistical significance (OR = 1.49; 95% CL = 0.99, 2.27).

CONCLUSION

In the future, the primary prevention or effective treatment of cerebrovascular disease, arthritis, and possibly coronary artery disease may produce a modest reduction in the incidence of severe functional limitation.

Screening elders for risk of hospital admission

OBJECTIVE

To define a set of screening criteria that identifies elders who are at high risk for repeated hospital admission in the future.

DESIGN

Longitudinal cohort study. Logistic regression analysis of data from half of the subjects was used to identify risk factors for repeated hospital admission. The ability of these risk factors to identify elders who are at high risk for repeated hospitalization in the future was then tested using data from the other half of the subjects.

SETTING

United States.

PARTICIPANTS

A subsample (n = 5876) of a multistage probability sample of all non-institutionalized U.S. civilians who were 70 years or older in 1984.

MEASUREMENTS

At baseline (1984), elderly subjects were asked about their demographic, socioeconomic, medical, and functional characteristics and about their recent use of health services. Their subsequent hospital admissions and mortality were then monitored through the records of the Medicare program and the National Death Index (1985-88).

RESULTS

Among the subjects in the first half of the sample, eight factors emerged as risk factors for repeated admission: older age, male sex, poor self-rated general health, availability of an informal caregiver, having ever had coronary artery disease, and having had, during the previous year, a hospital admission, more than six doctor visits, or diabetes. Based on the presence or absence of these factors in 1984, 7.2% of the subjects in the second half of the sample were estimated to have a high probability of repeated admission (Pra > or = 0.5) during 1985-1988. In comparison with subjects estimated to have a low risk (Pra < 0.5), this high-risk group's actual experiences during 1985-1988 included a higher cumulative incidence of repeated admission (41.8% vs 26.2%, P < 0.0001), a higher cumulative rate of mortality (44.2% vs 19.0%, P < 0.0001), more hospital days per person-year survived (5.2 vs 2.6), and higher hospital charges per person-year survived ($3731 vs $1841).

CONCLUSION

Eight easily ascertained risk factors affect elders' probability of being hospitalized repeatedly within four years. In the future, brief surveys about the presence of these factors could be used to estimate elders' risk of future hospitalization and, thereby, to identify some of those who may derive the greatest benefit from interventions designed to avert the need for hospitalization.

Allocative efficiency of case managers for the elderly

This study presents an analysis of the allocative efficiency of case managers for the community-based elderly in an environment in which case management and a range of home and community-based services were available and directly linked to a mandatory preadmission screening program for nursing home applicants. We collected data for a one-year follow-up period on client placement, health and functional status, informal support, and use of health and social services for clients in two urban and two rural counties that participated in the Minnesota Pre-Admission Screening/Alternative Care Grants Program (PAS/ACG). We found that among those receiving ACG-supported services, the relationship between variation in the level of support for home and community-based services and the length of time elderly clients remained in the community suggested that case managers were allocating home and community-based services in a reasonably efficient manner. This finding offers support for using case managers to target services to the elderly.

Substitution of formal and informal care for the community-based elderly

The Minnesota Pre-Admission Screening/Alternative Care Grants Program screens those at risk of nursing home placement and funds services that will allow the elderly to be cared for at home. Information was collected for a 1-year period on client placement, health and functional status, informal support, use of health and formal services, and care-giver characteristics for 214 clients screened during the last quarter of 1984. A two-equation model was hypothesized to examine the formal service decisions of case managers and the amount of informal care provided for elderly clients at risk of institutionalization. A system of two simultaneous equations was estimated using a two-stage least-squares approach. The findings suggest that case managers allocate formal services based primarily on client need. The amount of informal care provided to clients did not affect significantly the decisions of case managers and is not determined significantly by the amount of formal services received by the elderly in the community. The lack of substitution between formal services and informal care reinforces the findings of previous research.