Plasma orexin-A levels in patients with delirium

Suvorexant for the prevention of delirium: A meta-analysis

BACKGROUND

Delirium is a frequently encountered complication, which is associated with increased mortality. Suvorexant, an approved agent for the treatment of insomnia, is recently suggested to be also effective for prevention of delirium by some authors. However, a consensus has yet to be reached. The goal of this study was to perform a meta-analysis to overall estimate the effectiveness of suvorexant in preventing delirium and its related consequences.

METHODS

Eligible studies were identified by searching online databases of PubMed, EMBASE, and Cochrane Library. The pooled OR was calculated for binary outcomes (e.g., the incidence of delirium, mortality, or adverse events), while standardized mean difference (SMD) were expressed for continuous outcomes (e.g., time to delirium onset, length of stay in hospital and ICU, time on ventilation).

RESULTS

Seven studies which comprised 402 suvorexant treatment patients and 487 patients with control treatment were included in this meta-analysis. Overall, pooled analysis indicated the incidence of delirium could be significantly reduced (OR, 0.30; P < .001) and time to delirium onset was significantly lengthened (SMD, 0.44; P = .006) in patients undergoing suvorexant treatment compared with controls. Suvorexant had no beneficial effects on the secondary outcomes [length of stay in hospital (SMD, -0.65; P = .161) and ICU (SMD, 0.34; P = .297), time on ventilation (SMD, 1.09; P = .318), drug-related adverse events (OR, drug-related adverse events (OR, 1.66; P = .319) and mortality (OR, 2.21; P = .261)]. Subgroup analysis also confirmed the benefit of suvorexant on the development of delirium, which was significant in any subgroup.

CONCLUSION

Suvorexant should be recommended for the prevention of delirium in clinic.

Plasma orexin-A-like immunoreactivity levels and renal function in patients in a geriatric ward

Orexin-A is a neuropeptide mainly produced by hypothalamic neurons with functions in the central nervous system such as regulation of the sleep-wake cycle. Recent studies suggest that orexin-A also plays major roles in peripheral tissues. Although a few studies have reported a role for the kidney in the dynamics of orexin-A, little is known about the association between plasma orexin-A-like immunoreactivity (orexin-A-LI) levels and renal function. We evaluated this association, and also explored other clinical characteristics associated with plasma orexin-A-LI levels. In this cross-sectional study, we included 70 consecutive patients aged ≥65 years admitted to the geriatric ward of Nagoya University Hospital from December 2017 to January 2018. Patients taking suvorexant (an orexin receptor antagonist) were excluded. On hospital days 2-4, fasting blood was collected in the morning. We evaluated associations between plasma orexin-A-LI levels and renal function and other clinical characteristics. Renal function was evaluated in two ways: the estimated glomerular filtration rate (eGFR) using serum creatinine, and estimated creatinine clearance (eCrCl) using the Cockroft-Gault formula. Pearson's correlation coefficient revealed that plasma orexin-A-LI levels were negatively correlated with the eGFR (r = -0.351, p = 0.003) and eCrCl (r = -0.342, p = 0.004). There were no significant associations between plasma orexin-A-LI levels and the primary diagnosis, body mass index, duration of fasting, or other clinical characteristics. In conclusion, plasma orexin-A-LI levels were negatively correlated with renal function in patients in a geriatric ward. Renal function may affect the study design and data interpretation in studies of plasma orexin-A-LI.