Table 3. Responders.
| Observed unadjusted number (%) of responders | Slope (95%CI) | Adjusted risk difference in responders (95% CI) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
|
| ||||||||||
| Time | Oregon | Minnesota | SMT 0 | SMT 6 | SMT 12 | SMT 18 | per 6 SMT sessions | SMT 0 vs SMT 6 | SMT 0 vs SMT 12 | SMT 0 vs SMT 18 |
| Cervicogenic headache days (≥30% improvement) | ||||||||||
| 6 wk | 49 (40.8%) | 66 (51.6%) | 25 (41.7%) | 25 (39.7%) | 30 (48.4%) | 35 (55.6%) | 0.06 (0.01, 0.12)* | -0.02 (-0.18, 0.15) | 0.10 (-0.07, 0.27) | 0.17 (-0.00, 0.35) |
| 12 wk | 57 (50.0%) | 71 (55.9%) | 23 (39.7%) | 29 (46.0%) | 31 (52.5%) | 45 (73.8%) | 0.11 (0.06, 0.17)* | 0.08 (-0.09, 0.25) | 0.17 (0.01, 0.33)* | 0.35 (0.18, 0.52)* |
| 24 wk | 59 (56.2%) | 79 (62.7%) | 28 (52.8%) | 34 (57.6%) | 32 (54.2%) | 44 (73.3%) | 0.08 (0.03, 0.13)* | 0.09 (-0.08, 0.26) | 0.06 (-0.10, 0.23) | 0.27 (0.11, 0.43)* |
| 39 wk | 68 (65.4%) | 78 (62.4%) | 30 (56.6%) | 38 (64.4%) | 38 (65.5%) | 40 (67.8%) | 0.05 (-0.00, 0.11) | 0.11 (-0.07, 0.28) | 0.11 (-0.07, 0.28) | 0.17 (-0.00, 0.34) |
| 52 wk | 64 (62.1%) | 77 (61.6%) | 31 (59.6%) | 31 (53.4%) | 36 (62.1%) | 43 (71.7%) | 0.07 (0.01, 0.12)* | -0.01 (-0.18, 0.17) | 0.07 (-0.10, 0.24) | 0.20 (0.04, 0.37)* |
| Cervicogenic headache days (≥50% improvement) | ||||||||||
| 6 wk | 31 (25.8%) | 38 (29.7%) | 14 (23.3%) | 13 (20.6%) | 19 (30.6%) | 23 (36.5%) | 0.05 (0.00, 0.10)* | -0.02 (-0.16, 0.13) | 0.09 (-0.06, 0.25) | 0.14 (-0.01, 0.31) |
| 12 wk | 41 (36.0%) | 53 (41.7%) | 17 (29.3%) | 17 (27.0%) | 26 (44.1%) | 34 (55.7%) | 0.10 (0.04, 0.15)* | -0.02 (-0.18, 0.13) | 0.17 (0.02, 0.33)* | 0.26 (0.09, 0.43)* |
| 24 wk | 42 (40.0%) | 57 (45.2%) | 19 (35.8%) | 21 (35.6%) | 27 (45.8%) | 32 (53.3%) | 0.06 (0.00, 0.11)* | -0.01 (-0.18, 0.14) | 0.11 (-0.05, 0.27) | 0.15 (-0.02, 0.32) |
| 39 wk | 55 (52.9%) | 61 (48.8%) | 21 (39.6%) | 32 (54.2%) | 30 (51.7%) | 33 (55.9%) | 0.05 (-0.00, 0.11) | 0.14 (-0.04, 0.31) | 0.13 (-0.04, 0.31) | 0.18 (-0.01, 0.35) |
| 52 wk | 52 (50.5%) | 51 (40.8%) | 21 (40.4%) | 24 (41.4%) | 28 (48.3%) | 30 (50.0%) | 0.05 (-0.01, 0.10) | 0.03 (-0.14, 0.20) | 0.11 (-0.06, 0.28) | 0.13 (-0.04, 0.31) |
CI, confidence interval; UWS, University of Western States; NWHSU, Northwestern Health Sciences University; SMT, spinal manipulation. Unadjusted group counts and percentages are from original data without imputation; slopes and risk differences in responders across groups are computed from imputed data and adjusted for baseline covariates. Positive signs of slopes and risk differences favor higher doses of manipulation.
*
p<.05.