Table 1.
Characteristics of Patients Included in Each Sample for Chronic Low-Back Pain and Chronic Neck Pain
Chronic Low-Back Pain Chronic Neck Pain Full
Sample1Revealed WTP
Sample2Pain
Reduction
Sample3Full
Sample1Revealed
WTP
Sample2Pain
Reduction
Sample3Variable N 865 762 488 718 632 392 Income, N (%) Less than $20,000 34 (4%) 32 (4%) 17 (3%) 20 (3%) 18 (3%) 7 (2%) $20,000 to $39,999 119
(14%)102
(13%)54 (11%) 64 (9%) 57 (9%) 28 (7%) $40,000 to $59,999 139
(16%)127
(17%)85 (17%) 126
(18%)115
(18%)67 (17%) $60,000 to $99,999 230
(27%)200
(26%)126
(26%)196
(27%)175
(28%)110
(28%)$100,000 to $199,999 198
(23%)180
(24%)124
(25%)183
(25%)158
(25%)109
(28%)$200,000 or more 37 (4%) 33 (4%) 20 (4%) 36 (5%) 32 (5%) 20 (5%) Prefer not to answer or not stated 108
(12%)88
(12%)62 (13%) 93
(13%)77 (12%) 51 (13%) Working full- or part-time, N (%) 654
(76%)576
(76%)368
(75%)592
(82%)518
(82%)329
(84%)Years of pain, N (%) Less than 1 Year 115
(13%)99
(13%)*72 (15%) 82
(11%)69
(11%)†55 (14%) 1 Year to Less than 2 Years 61 (7%) 54
(7%)*38 (8%) 39 (5%) 36 (6%)† 20 (5%) 2 Years to Less than 5 Years 120
(14%)99
(13%)*73 (15%) 113
(16%)97
(15%)†70 (18%) 5 Years to Less than 10 Years 139
(16%)123
(16%)*71 (15%) 139
(19%)120
(19%)†74 (19%) 10+ Years 413
(48%)372
(49%)*227
(47%)326
(45%)295
(47%)†164
(42%)Age in years, Mean (SD) 48.38
(14.9)48.37
(14.8)48.53
(14.7)45.56
(12.9)45.59
(13.1)45.96
(13.0)Age in years, N (%) Gender: Female, N (%) 561
(65%)493
(65%)†298
(61%)†586
(82%)†526
(83%)319
(81%)Less than a Bachelors degree, N (%) 397
(46%)343
(45%)†196
(40%)‡294
(41%)253
(40%)145
(37%)*Depression, N(%) 215
(25%)195
(26%)*113
(23%)181
(25%)*168
(27%)98 (25%) ODI Score, Mean (SD) 20.45
(12.5)20.5
(12.3)‡19.22
(11.7)‡18.25
(8.8)18.24
(8.9)†17.42
(8.1)†NDI Score, Mean (SD) 20.62
(9)20.53
(9.1)‡19.51
(8.2)‡22.70
(12.3)22.88
(12.3)‡21.35
(11.4)†At least some chiropractic coverage 595
(69%)523
(69%)340
(70%)481
(67%)428
(68%)271
(69%)Chiropractic visit frequency over 3 months, N (%) Monthly and less than monthly --- 261
(34%)175
(36%)--- 192
(30%)124
(32%)Biweekly up to monthly --- 208
(27%)132
(27%)--- 202
(32%)123
(31%)Weekly up to biweekly --- 194
(25%)116
(24%)--- 153
(24%)91 (23%) More than weekly --- 99
(13%)65 (13%) --- 85 (13%) 54 (14%) Unknown --- 0 (0%) 0 (0%) --- 0 (0%) 0 (0%) Have both CLBP and CNP 439
(51%)†401
(53%)246
(50%)426
(59%)382
(60%)233
(59%)ODI = Oswestry Disability Index; NDI = Neck Disability Index; WTP = Willingness to pay for pain reduction
1The Full Sample includes all patients who answered the WTP questions. Footnotes in this column relate to the statistical significance of the differences between the Full and Revealed WTP Samples.
2The Revealed WTP Sample includes those from the Full Sample who had chiropractic visits after baseline. Footnotes in this column relate to the statistical significance of the differences between the Revealed WTP and Pain Reduction Samples.
3The Pain Reduction Sample includes all those in the Revealed WTP Sample who had a reduction over 3 months in both actual pain and in reports of what their pain would have been without chiropractic care.
Footnotes in this column relate to the statistical significance of the differences between the Full and Pain Reduction Samples.
*Differences are statistically significant at p<.05. †Differences are statistically significant at p<.01. ‡Differences are statistically significant at p<.001.