The Relationship Between Diabetes Mellitus And Hypothalamic-Pituitary-Adrenal Axis: A Systematic Review

Objective To provide objective evidences for early screening of the hypothalamic-pituitary-adrenal(HPA) axis function in diabetic patients, the relationship between HPA axis function and diabetes mellitus was systematically reviewed.Methods We searched for original articles in Pub Med,Ovid,Embase, Web of science Database from inception to 31 th December 2014.We reviewed articles that involving the relationship between HPA axis function and diabetes mellitus. No language or date restrictions were applied.The meta-analysis was performed by using the stata 12.0 software.Results Twenty three studies including 7726 participants(1507 diabetic patients and 6219 controls) were ultimately taken into analysis,among 18 were case-control studies and,5 were cross-sectional studies. Our meta-analysis shows the following results: Firstly, compared with control group, the basal plasma cortisol level in total diabetes group,T1 DM group and T2 DM group was significantly higher. Compared with control group,diabetes patients(with or without chronic complications) combined with hypertension exhibits a higher level of basal plasma cortisol, however, diabetic patients with normal blood pressure shows a similar level of basal plasma cortisol. Second, there were no obvious differences in the 24 hours urinary free cortisol(24h UFC) and ACTH levels between diabetes group and control group.Third,compared with control group, postdexamethasone cortisol level was markedly higher in diabetes group. Forth, the differences of awaking salivary cortisol and cortisol awakening response(CAR) between the two groups were inconsistent among all included studies.Conclusions This present analysis has demonstrated that basal plasma cortisol and postdexamethasone cortisol in diabetes patients are indeed higher compared with control group,suggesting that HPA axis dysfunction may exist along with diabetes mellitus, and diabetic comorbidity may worsen the HPA axis dysfunction. However,24 h UFC and ACTH levels were not altered between the two groups. The CAR in most diabetes groups was reduced,also suggesting that HPA axis dysfunction may exist along with diabetes mellitus.Further researches are needed to confirm the relationship between hypothalamic-pituitary-adrenal axis function and diabetes mellitus.