Risk factors for incident delirium among urological patients: a systematic review and meta-analysis with GRADE summary of findings.

BACKGROUND: Post-operative delirium is an important, yet under-researched complication of surgery. Patients undergoing urological surgery may be at especially high risk of POD, as they are often older, and interventions can be associated with conditions that trigger delirium. The main aim of this systematic review was to evaluate the available evidence for risk factors in this patient group. METHODS: Five databases were searched (MEDLINE, Web of Science, EMBASE, CINAHL and PsychInfo) between January 1987 and June 2019. The Newcastle-Ottawa Scale was used to assess for risk of bias. Pooled odds ratio or mean difference (MD) for individual risk factors were estimated using the Mantel-Haenzel and inverse variance methods. RESULTS: Seven articles met the inclusion criteria, giving a total population of 1937. The incidence of POD ranged from 5 to 29%. Three studies were deemed low risk of bias and four at a high risk of bias. Nine risk factors were suitable for meta-analysis, with age (MD 4.314 95% CI 1.597, 7.032 p = 0.002) and the clock drawing test (MD - 2.443 95% CI - 3.029, - 1.857 p < 0.001) having a statistically significant association with POD in pooled analyses. CONCLUSION: Delirium is common in urological patients. This review has identified a lack of studies in this surgical population, with wide heterogeneity and high risk of bias. It also highlights a number of potential risk factors for post-operative delirium, of which some are modifiable. However, the strength of evidence is weak at present and so future research should focus on assessing comparable risk factors in this patient group in order to inform future clinical practice. Review registration The review protocol was prospectively registered with the PROSPERO database (reference CRD42017054613).

Systematic review and meta-analysis of risk factors for postoperative delirium among older patients undergoing gastrointestinal surgery.

BACKGROUND: Postoperative delirium (POD) is common after surgery. As age is a known risk factor, the increased ageing of the population undergoing surgery emphasizes the importance of the subject. Knowledge of other potential risk factors in older patients with surgical gastrointestinal diseases is lacking. The aim here was to collate and synthesize the published literature on risk factors for delirium in this group. METHODS: Five databases were searched (MEDLINE, Web of Science, Embase, CINAHL(®) and PSYCinfo(®) ) between January 1987 and November 2014. The Newcastle-Ottawa Scale was used to rate study quality. Pooled odds ratios or mean differences for individual risk factors were estimated using the Mantel-Haenszel and inverse-variance methods. RESULTS: Eleven studies met the inclusion criteria; they provided a total of 1427 patients (318 with delirium and 1109 without), and predominantly included patients undergoing elective colorectal surgery. The incidence of POD ranged from 8·2 to 54·4 per cent. A total of 95 risk factors were investigated, illustrating wide heterogeneity in study design. Seven statistically significant risk factors were identified in pooled analysis: old age, American Society of Anesthesiologists (ASA) physical status grade at least III, body mass index, lower serum level of albumin, intraoperative hypotension, perioperative blood transfusion and history of alcohol excess. Patients with POD had a significantly increased duration of hospital stay and a higher mortality rate compared with those without delirium. CONCLUSION: Delirium is common in older patients undergoing gastrointestinal surgery. Several risk factors were consistently associated with POD.