Dementia is a chronic and progressive neurological condition characterised by cognitive and functional impairment. It is often associated with multimorbidity and imposes a significant economic burden on healthcare systems and families, especially in low-income and middle-income countries. In Peru, where dementia cases are increasing rapidly, timely detection and referral for diagnosis is crucial. This protocol is part of the IMPACT Salud project in Peru. Here, we focus on a specific component aimed at validating an mHealth tool for the detection of cognitive and functional impairment and assessing its cost-effectiveness. We will also assess changes in cognitive and functional impairment as well as health economic outcomes over 1 year.

This observational study will be conducted in four geographically diverse regions of Peru. Community health workers are expected to contact approximately 32 000 participants (≥60 years) to apply an mHealth-enabled tool that includes cognitive and functional instruments: Ascertain Dementia 8, Peruvian version of Rowland Universal Dementia Assessment Scale and Pfeffer Functional Activities Questionnaire. From this large sample, we aim to find 3600 participants and their study partners to enrol and interview at baseline regarding sociodemographic characteristics, lifestyles, comorbidities and health economic data including resource use, costs and health-related quality of life (HR-QoL). Psychologists, blind to previous results, will assess dementia stage of the participants using an abbreviated Clinical Dementia Rating (CDR) scale. At 6-month follow-up, participants will complete a brief health economics questionnaire on resource use, costs and HR-QoL. To validate the accuracy of the detection tool, a subsample of 600 participants who completed the baseline will undergo a gold-standard clinical neuropsychological assessment. This subsample will participate in a 12-month follow-up, including health economics, cognitive and functional impairment tests and the CDR scale. Results will be analysed and presented by cognitive status, site, sex and multimorbidity profile. Finally, data from all stages and external sources will inform a decision model to implement a cost-effectiveness analysis of the detection tool at the national level.

The study received ethics approval in Peru (Universidad Peruana Cayetano Heredia: CONSTANCIA-CIEI-378-33-23) and in the UK (Imperial College London: ICREC/SETREC reference number 6647445). Informed consent will be obtained from participants and their study partners, considering the participant’s capacity to consent. For illiterate participants, consent will be obtained through a witnessed procedure involving study partners, with a fingerprint obtained instead of a signature. The results will be disseminated through conferences, published articles, public presentations (particularly to those involved in dementia care) and presentations or meetings with local health authorities.

To evaluate the diagnostic accuracy of CT in identifying small and large bowel obstruction and associated complications, including ischaemia and perforation, in adult patients.

Systematic review and meta-analysis reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses of Diagnostic Test Accuracy reporting guidelines.

Ovid MEDLINE and Embase were searched from 1946 to 20 February 2025.

The study included randomised controlled trials, cohort studies and case–control studies evaluating the diagnostic accuracy of CT for bowel obstruction in adults (aged ≥18 years). Only studies published in English were included. Conversely, case reports, editorials, conference abstracts without full data and studies focusing exclusively on paediatric populations or animal models were excluded.

Three reviewers independently extracted data on study characteristics, CT modality, diagnostic accuracy metrics (sensitivity, specificity and predictive values) and complications. Risk of bias was assessed using the QUADAS-2 tool. A random-effects meta-analysis was conducted. Heterogeneity was assessed using I² and Tau² statistics.

Sixty-five studies with 9418 patients were included. The pooled sensitivity and specificity of CT for bowel obstruction were 90% (95% CI 78 to 96; I²=56%, Tau²=0.36) and 88.8% (95% CI 78.0 to 94.8; I²=65%, Tau²=0.35), respectively. For bowel ischaemia, CT showed a pooled sensitivity of 47.0% (95% CI 32.4 to 59.9; I²=0%, Tau²=0.00) and specificity of 85.3% (95% CI 77.9 to 89.5; I²=1%, Tau²=0.45). Multidetector CT (MDCT) outperformed older modalities across all endpoints. Ischaemia was present in 22.05% of all cases, with higher rates in small bowel obstruction. Perforation and mortality rates were 3.98% and 4.40%, respectively. No significant publication bias was detected, and the certainty of evidence was graded as moderate for most diagnostic accuracy outcomes.

CT, particularly MDCT, offers high diagnostic accuracy for bowel obstruction and is a critical tool for detecting serious complications such as ischaemia and perforation. However, sensitivity for ischaemia remains modest. Standardised protocols and prospective studies are needed to enhance early identification and optimise care pathways.