A Mysterious Role of Arginine Vasopressin Levels in Meniere's Disease-Meta-analysis of Clinical Studies

Objective: There are contradicting claims that patients with Me ' nie` re's disease (MD) have elevated levels of arginine vasopressin (AVP). The results of published studies regarding the difference of AVP level between MD patients and non-MD control subjects are inconsistent. We propose that the discrepancy of AVP levels during different MD phases may be a potential reason. Thus, we conducted a metaanalysis to analyze the precise estimate of this hypothesis. Data Sources: PubMed, Medline, and Cochrane databases from the earliest publication, up until September 2016; references from meta-analyses and related review articles. Study Selection and Data Extraction: Clinical studies that reported AVP level in MD patients and non-MD controls were independently reviewed according to the inclusion criteria. The Newcastle-Ottawa Scale was used to assess quality of studies. Data Synthesis: Random effects model was used to calculate the weighted mean difference. Conclusion: Eight studies met the inclusion criteria. AVP levels of MD patients in acute phase (WMD - 2.29, 95% CI = 0.84-3.74, Z = 3.10, p = 0.002) were significantly higher than non-MD subjects. For MD patients in remission phase the difference of AVP levels between the MD patients and the non-MD controls was found (WMD = 0.54, 95% CI - - 0.06 to 1.02, Z - 2.20, p - 0.03). However, AVP level was not an ideal biomarker of MD patients. Regardless of MD phase, there were no significant differences in the AVP level of MD patients (WMD = 0.27, 95% CI = -0.10 to 0.64, Z = 1.43, p = 0.15). Future investigations with larger sample sizes are needed to verify the results.