Table 1.
Baseline Characteristics of Participants
| Total (N = 625) | No remission (N = 480)a | Prolonged remission (N = 125) | p Value | |
| Interviewed | 144 (23) | 19 (4) | 125 (100) | |
| Prolonged remissionb | 125 (23) | 0 (0) | 125 (100) | |
| Attack free, y | 0.5 (0.2–3.1) | 0.2 (0.2–0.9) | 6 (4–11) | <0.001d |
| Active CHc | 379 (61) | 246 (51) | 0 (0) | <0.001d |
| Prophylactic use | 257 (41) | 257 (54) | 0 (0) | <0.001d |
| Sex | 0.003d | |||
| Male | 424 (68) | 310 (65) | 98 (78) | |
| Female | 201 (32) | 170 (35) | 27 (22) | |
| Age at inclusion | 58 (48–67) | 57 (46–65) | 64 (55–70) | <0.001d |
| Age at CH onset | 29 (20–42) | 29 (20–43) | 27 (19–39) | 0.120 |
| Age at menarche | 13 (12–14) | 13 (11–14) | 14 (12–14) | 0.130 |
| Age at menopause | 49 (45–51) | 49 (45–51) | 51 (49–55) | 0.023d |
| Disease duration | 21 (13–31) | 20 (13–30) | 23 (15–33) | 0.053 |
| Episodic CHc | 372 (60) | 240 (50) | 113 (90) | <0.001d |
| Subtype switch | 167 (27) | 146 (30) | 21 (17) | <0.001d |
| Attack frequency | 3 (1–4) | 3 (1–4) | 3 (1–5) | 0.600 |
| Attack intensity | 9 (8–10) | 9 (8–10) | 9 (9–10) | <0.001d |
| Autonomic symptoms | 583 (94) | 456 (95) | 111 (90) | 0.017d |
| Restlessness | 562 (90) | 431 (90) | 113 (90) | 0.900 |
| Episode duration, wk | 8 (5–13) | 8 (6–13) | 8 (5–12) | 0.300 |
| Between-episode interval, mo | 9 (5–12) | 9 (6–18) | 9 (4–12) | 0.058 |
| Comorbid headache | 178 (29) | 140 (29) | 31 (25) | 0.500 |
| Smoker | 165 (27) | 143 (30) | 17 (14) | <0.001d |
| Positive family history | 67 (11) | 47 (9.8) | 17 (14) | 0.200 |
| Right-sided attacks | 256 (41) | 198 (41) | 47 (38) | 0.500 |
| Bilateral attacks | 12 (1.9) | 8 (1.7) | 3 (2.4) | 0.700 |
Abbreviations: CH = cluster headache; IQR = interquartile range.
Descriptives are depicted as median (IQR) or n (%).
a
Twenty of 625 screened positive for remission in the questionnaire, but criteria could not be verified because of unavailability for phone interview. These 20 patients were, therefore, excluded from group comparison (remission vs no remission), resulting in N = 480 participants without remission (and not 625–125 = 500).
b
Verified prolonged remission based on the following: screened positive in the survey and remission criteria were confirmed during the telephone interview.
c
Active CH: having CH attacks in the month of inclusion.
d
Statistically significant result.