Results and lessons learnt from a randomized controlled trial: prophylactic treatment of vestibular migraine with metoprolol (PROVEMIG)

Table 2 Summary of diary-based primary and secondary end points for the full analysis set population

	N^a	Placebo	Metoprolol
Primary end point
Vertigo attacks, monthly^b incidence rates (95% CI)^a	114
Month 4		4.499 (3.295–5.704)	4.202 (3.138–5.267)
Month 5		3.733 (2.527–4.939)	3.428 (2.384–4.471)
Month 6		3.097 (1.914–4.281)	2.796 (1.792–3.800)
Decay rate (95% CI), P value		0.830 (0.776–0.887), <0.001
IRR (95% CI), P value		0.983 (0.902–1.071), 0.696
Secondary end points
Vertigo days, monthly^b incidence rates (95% CI)^a	114
Month 4		6.757 (5.067–8.447)	5.278 (3.999–6.557)
Month 5		5.881 (4.126–7.637)	4.319 (3.070–5.569)
Month 6		5.119 (3.326–6.912)	3.534 (2.334–4.735)
Decay rate (95% CI), P value		0.870 (0.821–0.923), <0.001
IRR (95% CI), P value		0.940 (0.869–1.017), 0.125
Mean monthly^b MHDs^c	91
Months 4–6		2.400 (1.410–4.410)	2.505 (1.488–4.215)
IRR (95% CI), P value		1.048 (0.482–2.250), 0.904

CI confidence interval
^a Primary efficacy analysis by a Poisson generalized linear mixed model (with random intercept and slope) based on the whole 6-month treatment period; assumption is maximal effect of intervention during the pre-specified 90-day assessment period in months 4–6; analysis of vertigo day rates performed as a supplementary analysis
^b Mean incidence rates per 30 days derived by a model-based approach assuming missingness at random; pre-specified time period of primary interest months 4–6; reference group = placebo
^c Migraine headache days (MHDs): rates and incidence rate ratios (IRRs) are estimated from a negative binomial generalized linear model based on the aggregated MHD data reported within months 4–6 only (91 patients contributing MHD-related diary documentation)

ISSN: 1745-6215