Incidence of dizziness and vertigo in Japanese primary care clinic patients with lifestyle-related diseases: an observational study

OBJECTIVE Dizziness and vertigo are highly prevalent symptoms among patients presenting at primary care clinics, and peripheral vestibular disorder (PVD) is their most frequent cause. However, the incidence of PVD has not been well documented. This study aimed to investigate the incidence of dizziness, vertigo, and PVD among patients presenting at a primary care clinic. DESIGN This was an observational study. SETTING AND PARTICIPANTS Between November 2011 and March 2013, we observed 393 patients, all at least 20 years old, who had been treated for chronic diseases such as hypertension, dyslipidemia, and diabetes mellitus for at least 6 months at a primary clinic (Oki Clinic) in Japan. OUTCOME The main outcome of interest was new incidence of dizziness, vertigo, and PVD events. During the 1-year follow-up period, the otorhinolaryngologist diagnosed and reported new PVD events. RESULTS The mean age of the 393 participants at entry was 65.5 years. Of the study participants, 12.7%, 82.4%, and 92.6% had diabetes mellitus, hypertension, and dyslipidemia, respectively. We followed up all the participants (100%). During the 662.5 person-years of follow-up, 121 cases of dizziness or vertigo (dizziness/vertigo) and 76 cases of PVD were observed. The incidence of dizziness/vertigo and PVD was 194.7 (95% confidence interval: 161.6-232.6) per 1,000 person-years and 115.7 (95% confidence interval: 92.2-142.6) per 1,000 person-years, respectively. There were 61 cases of acute peripheral vestibulopathy, 12 of benign paroxysmal positional vertigo, and three of Meniere's disease among the 76 PVD patients. CONCLUSION We reported the incidence of dizziness/vertigo among Japanese primary care clinic patients, which was higher than that usually observed in the general population. Furthermore, we described the incidence of PVD and found that it was a major cause of dizziness/vertigo.