Table 5.

Longitudinal studies focusing on PPI treatment.

Author	Type	Sample	Selection criteria	Measure	Risk of bias/EBM level	Result
Vaezi et al. (2010)33	Controlled randomized test	75	Postnasal drip with no CRS or allergy	Symptoms evaluation and pH-metry using PPI	High/	Important improvement of symptoms compared to control group
DiBaise et al. (2002)34	Cohort	11	CRS that is refractory to medical and surgical treatment	Symptoms score, pH-metry via dual-channel tube, nasolaryngoscopy after PPI treatment for 3 months	Mod/4	Mild improvement of symptoms
Pincus et al. (2006)35	Cohort	30	CRS that is refractory to medical and surgical treatment	Evaluation of symptoms and pH-metry using PPI	High/4	25 of 30 had LPR or nasal reflux events. 14 of 15 improved with PPI
Durmus et al. (2010)36	Case–control	50 vs. 30	GERD and LPR vs. absence of GERD	Nasal saccharin test and clinical evaluation before and after treatment with PPI	Mod/2b	No difference on saccharin test. There was significant improvement of symptoms

CRS, chronic rhinosinusitis; LPR, laryngopharyngeal reflux; PPI, proton pump inhibitor; GERD, gastroesophageal reflux disease.