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Table 2 Differences in clinical and patient reported characteristics (not used in clustering) across clusters (total population)

From: AxSpA patients who also meet criteria for fibromyalgia: identifying distinct patient clusters using data from a UK national register (BSRBR-AS)

 

Cluster 1

Cluster 2

Cluster 3

Cluster 4

p value

N (%)

N (%)

N (%)

N (%)

Categorical variable

 Gender

  male

13 (40.6)

209 (60.2)

297 (69.6)

298 (64.5)

p < 0.001

  female

19 (59.4)

138 (39.8)

130 (30.4)

164 (35.5)

 Smoking Status

  never

10 (31.2)

129 (37.6)

201 (47.4)

214 (46.8)

p < 0.001

  ex

14 (43.8)

116 (33.8)

168 (39.6)

180 (39.4)

  current

8 (25.0)

98 (28.6)

55 (13.0)

63 (13.8)

 Alcohol Use

  never

1 (3.1)

39 (11.4)

20 (4.7)

25 (5.5)

p < 0.001

  ex

9 (28.1)

94 (27.5)

41 (9.7)

63 (13.9)

  current

22 (68.8)

209 (61.1)

361 (85.6)

366 (80.6)

 Employed

  no

15(46.9)

164 (47.3)

113 (26.5)

160 (34.9)*

p < 0.001

  yes

17 (53.1)

183 (52.7)

314 (73.5)

299 (65.1)

 Job type

  mainly sedentary

8 (50.0)

81 (45.5)

171 (56.1)

179 (61.5)

p = 0.009

  mainly physical

8 (50.0)

97 (54.5)

134 (43.9)

112 (38.5)

 Current biologic therapy

  no

22 (68.8)

211 (61.0)

364 (86.3)

350 (76.1)*

p < 0.001

  yes

10 (31.2)

135 (39.0)

58 (13.7)

110 (23.9)

 NSAID (last 6 m)

  no

7 (21.9)

114 (32.9)

136 (31.9)

142 (30.7)

p = 0.611

  yes

25 (78.1)

233 (67.1)

291 (68.1)

320 (69.3)

 DMARD use in past 6 m

  no

21 (65.6)

305 (87.9)

374 (87.6)

401 (86.8)

p = 0.004

  yes

11 (34.4)

42 (12.1)

53 (12.4)

61 (13.2)

 HLA B27 status

  positive

20 (62.5)

148 (42.7)

260 (60.9)

242 (52.4)*

p < 0.001

  negative

7 (21.9)

58 (16.7)

52 (12.2)

66 (14.3)

  untested

5 (15.6)

141 (40.6)

115 (26.9)

154 (33.3)

 

Mean (95% CI)

Mean (95% CI)

Mean (95% CI)

Mean (95% CI)

 

Age

 years

49.5 (45.2, 53.8)

47.5 (46.0, 48.9)

49.4 (48.1, 50.7)

50.3 (48.9, 51.6)

p = 0.062

Age at symptom onset

 years

31.7 (27.7, 35.7)

30.7 (29.3, 32.0)

28.8 (27.8, 29.8)

29.7 (28.6, 30.8)

p = 0.074

Disease Activity

 BASDAI: 0 (best) – 10 (worst)

6.7 (5.9, 7.4)

6.7 (6.5, 6.9)

2.5 (2.3, 2.6)

4.5 (4.3, 4.7)*

p < 0.001

Disease Activity

 ASDAS Score

3.6 (3.2, 4.0)

3.7 (3.6, 3.8)

2.2 (2.1, 2.3)

2.9 (2.7, 3.0)*

p < 0.001

Physical Function

 BASFI: 0 (best) – 10 (worst)

6.2 (5.4, 6.9)

6.5 (6.3, 6.8)

2.5 (2.3, 2.7)

4.3 (4.0, 4.5)*

p < 0.001

Spinal Mobility

 BASMI: 0 (best) – 10 (worst)

4.2 (3.6, 4.8)

4.1 (3.8, 4.3)

3.4 (3.2, 3.6)

3.7 (3.4, 3.9)

p < 0.001

Patient Global

 BASG: 0 (best) – 10 (worst)

6.9 (6.2, 7.5)

7.0 (6.8, 7.2)

2.6 (2.4, 2.8)

4.6 (4.3, 4.8)*

p < 0.001

Spinal Pain

 VAS: 0 (best) – 10 (worst)

5.1 (4.1, 6.2)

6.3 (6.1, 6.6)

2.2 (2.0, 2.4)

4.0 (3.7, 4.2)*

p < 0.001

SF12 Mental Component

 100 (best) – 0 (worst)

37.6 (33.0, 42.1)

35.2 (34.3, 36.1)

54.0 (53.3, 54.6)

47.2 (46.3, 48.0)*

p < 0.001

SF12 Physical Component

 100 (best) – 0 (worst)

32.3 (29.3, 35.3)

32.3 (31.2, 33.4)

46.2 (45.3, 47.1)

39.4 (38.4, 40.5)*

p < 0.001

Quality of Life

 ASQoL: 0 (best) – 18 (worst))

12.9 (11.3, 14.4)

13.3 (12.9, 13.7)

3.0 (2.7, 3.3)

7.9 (7.5, 8.3)*

p < 0.001

Work absence

 absenteeism (%)

17.4 (0.1, 34.7)

11.2 (7.7, 14.6)

0.4 (0.1, 0.7)

4.4 (2.6, 6.1)*

p < 0.001

Work impairment

 presenteeism (%)

48.6 (36.4, 60.7)

52.5 (49.0, 56.1)

15.1 (13.1, 17.0)

28.8 (26.3, 31.4)*

p < 0.001

Overall work impairment

 (%)

48.8 (35.7, 62.0)

55.1 (51.3, 58.9)

15.4 (13.4, 17.5)

30.4 (27.7, 33.2)*

p < 0.001

Other activity impairment

 (%)

63.1 (53.8, 72.4)

65.4 (63.1, 67.6)

19.8 (17.9, 21.7)

38.4 (36.1, 40.6)*

p < 0.001

  1. *significant difference between cluster 3 & 4 at p < 0.05