Pain severity and healthcare resource utilization in patients with osteoarthritis in the United States

Figures & data

Table 1. Demographics and clinical characteristics by pain severity^a

	Patient-reported pain severity
Characteristics	Overall (n = 841)	Mild (n = 382)	Moderate (n = 302)	Severe (n = 157)	p-value^c
Age, mean (SD)	64.6 (11.7)	62.4 (11.1)	66.2 (11.6)	66.9 (12.5)	<0.0001
Female, n (%)	512 (60.9)	231 (60.5)	171 (56.6)	110 (70.1)	0.0194
Ethnicity, white/Caucasian n (%)^b	654 (77.8)	286 (74.9)	245 (81.1)	123 (78.3)	0.1454
Long-term sick leave/retired/unemployed due to OA, n (%)	23 (6.1)	4 (3.0)	11 (7.2)	8 (9.1)	0.1236
Employment (full or part time), n (%)	359 (42.9)	195 (51.2)	109 (36.2)	55 (35.5)	<0.0001
BMI, mean (SD)	28.7 (5.8)	27.7 (5.1)	29.1 (5.6)	30.3 (7.2)	<0.0001
Obese; BMI ≥30, n (%)	297 (35.3)	103 (27.0)	121 (40.1)	73 (46.5)	<0.0001
Time since diagnosis, mean (SD), years	2.3 (3.8)	1.9 (2.9)	2.6 (4.4)	3.0 (4.8)	0.0686
Number of affected joints, mean (SD)	3.1 (2.5)	2.7 (2.1)	3.4 (2.7)	3.6 (2.8)	<0.0001
Physician-reported location of most troublesome joint, n (%)
Knee	362 (43.0)	154 (40.3)	132 (43.7)	76 (48.4)	0.2168
Back	179 (21.3)	62 (16.2)	77 (25.5)	40 (25.5)	0.0048
Hip	151 (18.0)	54 (14.1)	63 (20.9)	34 (21.7)	0.0306
Hands/Fingers	76 (9.0)	47 (12.3)	18 (6.0)	11 (7.0)	0.0099
Neck	62 (7.4)	29 (7.6)	24 (7.9)	9 (5.7)	0.6733
Shoulder	53 (6.3)	28 (7.3)	18 (6.0)	7 (4.5)	0.4390
Other (wrist, ankle, foot, elbow)	58 (6.9)	32 (8.4)	18 (6.0)	8 (5.1)	0.2852

^aPain intensity was based on pain over the last week using the 11-point Numeric Rating Scale including mild (0–3), moderate (4–6), and severe (7–10) pain categories.

^bOverall, ethnicity also included: 11% African American; 6% Hispanic/Latino; 3% Asian; 0.5% Middle Eastern; 1% mixed race.

^cp-value reflects a difference among severity groups in percentages for categorical outcomes and in means for continuous outcomes.

BMI = body mass index; OA = osteoarthritis; SD = standard deviation.

Table 2. Comorbid conditions according to OA pain severity^a

	Patient-reported pain severity
Comorbidity, n (%)	Overall (n = 841)	Mild (n = 382)	Moderate (n = 302)	Severe (n = 157)	p-value^b
Hypertension	477 (56.7)	191 (50.0)	189 (62.6)	97 (61.8)	0.0016
Dyslipidemia/high cholesterol	204 (24.3)	91 (23.8)	83 (27.5)	30 (19.1)	0.1343
Anxiety	138 (16.4)	47 (12.3)	54 (17.9)	37 (23.6)	0.0040
Depression	130 (15.5)	42 (11.0)	51 (16.9)	37 (23.6)	0.0008
Diabetes	129 (15.3)	50 (13.1)	49 (16.2)	30 (19.1)	0.1836
Chronic lower back pain	114 (13.6)	20 (5.2)	67 (22.2)	27 (17.2)	<0.0001
Thyroid disease	106 (12.6)	37 (9.7)	49 (16.2)	20 (12.7)	0.0378
Osteoporosis	81 (9.6)	18 (4.7)	36 (11.9)	27 (17.2)	<0.0001
Obesity	79 (9.4)	24 (6.3)	35 (11.6)	20 (12.7)	0.0173
Other gastrointestinal conditions	61 (7.3)	22 (5.8)	30 (9.9)	9 (5.7)	0.0807
Asthma	45 (5.4)	24 (6.3)	15 (5.0)	6 (3.8)	0.4800
Insomnia	41 (4.9)	10 (2.6)	16 (5.3)	15 (9.6)	0.0028
Coronary heart disease	38 (4.5)	9 (2.4)	17 (5.6)	12 (7.6)	0.0139
Arrhythmia	29 (3.4)	9 (2.4)	10 (3.3)	10 (6.4)	0.0669
Constipation	28 (3.3)	6 (1.6)	17 (5.6)	5 (3.2)	0.0133
Neuropathic pain	27 (3.2)	5 (1.3)	17 (5.6)	5 (3.2)	0.0063
Myocardial infarction	22 (2.6)	4 (1.0)	10 (3.3)	8 (5.1)	0.0143
Rheumatoid arthritis	21 (2.5)	4 (1.0)	11 (3.6)	6 (3.8)	0.0356
Mild renal disease	16 (1.9)	5 (1.3)	7 (2.3)	4 (2.5)	0.4808
Peripheral vascular disease	15 (1.8)	4 (1.0)	7 (2.3)	4 (2.5)	0.2926
Congestive heart failure	14 (1.7)	3 (0.8)	5 (1.7)	6 (3.8)	0.0525
None of these	143 (17.0)	84 (22.0)	34 (11.3)	25 (15.9)	0.0009

^aPain intensity was based on pain over the last week using the 11-point Numeric Rating Scale including mild (0–3), moderate (4–6), and severe (7–10) pain categories. Conditions occurring in >5% of sample or with rates >2 × different across severity groups are listed in the table.

^bp-value reflects a difference among severity groups in percentages for categorical outcomes and in means for continuous outcomes.

OA = osteoarthritis.

Table 3. Consultations with HCPs by pain severity^a

Physician Specialty	Patient-reported pain severity
	Overall (n = 841)	Mild (n = 382)	Moderate (n = 302)	Severe (n = 157)	p-value^d
Patient-reported specialties ever involved in treatment of OA, n (%)
Primary care physician	670 (79.7)	298 (78.0)	246 (81.5)	126 (80.3)	0.5278
Orthopedic surgeon	319 (37.9)	128 (33.5)	127 (42.1)	64 (40.8)	0.0526
Rheumatologist	266 (31.6)	108 (28.3)	94 (31.1)	64 (40.8)	0.0176
Physical therapist	137 (16.3)	63 (16.5)	45 (14.9)	29 (18.5)	0.6106
Chiropractor	62 (7.4)	14 (3.7)	30 (9.9)	18 (11.5)	0.0007
Pain specialist	61 (7.3)	11 (2.9)	23 (7.6)	27 (17.2)	<0.0001
Massage therapist	52 (6.2)	18 (4.7)	18 (6.0)	16 (10.2)	0.0551
Occupational therapist	40 (4.8)	28 (7.3)	6 (2.0)	6 (3.8)	0.0041
Neurologist	34 (4.0)	10 (2.6)	10 (3.3)	14 (8.9)	0.0024
Anesthesiologist	25 (3.0)	8 (2.1)	8 (2.6)	9 (5.7)	0.0943
Podiatrist	24 (2.9)	4 (1.0)	10 (3.3)	10 (6.4)	0.0024
Licensed acupuncture therapist	20 (2.4)	6 (1.6)	7 (2.3)	7 (4.5)	0.1434
Nurse practitioner	17 (2.0)	5 (1.3)	6 (2.0)	6 (3.8)	0.1787
Physician assistant	16 (1.9)	4 (1.0)	5 (1.7)	7 (4.5)	0.0353
Of those seeing select specialties
Patient-reported visits, mean (SD) visits/last 3 months^b
All healthcare providers	3.0 (4.20)	2.5 (3.49)	2.9 (3.00)	4.5 (6.91)	<0.0001
Primary care physician	1.5 (1.13)	1.3 (0.92)	1.5 (1.09)	1.8 (1.53)	0.0002
Rheumatologist	1.4 (1.03)	1.1 (0.75)	1.6 (1.11)	1.6 (1.19)	0.0009
Orthopedic surgeon	1.3 (1.07)	1.1 (0.96)	1.3 (1.11)	1.6 (1.16)	0.0129
Physical therapist	3.5 (4.86)	2.7 (3.73)	2.8 (3.23)	6.9 (7.41)	0.0008
Physician-reported: first specialty to see patient for symptoms of OA, n (%)
Primary care physician	679 (80.7)	302 (79.1)	246 (81.5)	131 (83.4)	0.4960
Rheumatologist	72 (8.6)	36 (9.4)	21 (7.0)	15 (9.6)
Orthopedic surgeon	69 (8.2)	34 (8.9)	26 (8.6)	9 (5.7)
Other	19 (2.3)	10 (2.6)	7 (2.4)	2 (1.3)
Physician-reported: first specialty to diagnose patient with OA, n (%)
Primary care physician	565 (67.2)	276 (72.3)	196 (64.9)	93 (59.2)	0.0030
Rheumatologist	153 (18.2)	59 (15.4)	53 (17.5)	41 (26.1)
Orthopedic surgeon	109 (13.0)	45 (11.8)	46 (15.2)	18 (11.5)
Other	13 (1.5)	2 (0.5)	6 (2.0)	5 (3.2)
Physician-reported: first specialty to initiate OA treatment for patient, n (%)
Primary care physician	522 (62.1)	248 (64.9)	184 (60.9)	90 (57.3)	0.0003
Rheumatologist	155 (18.4)	60 (15.7)	50 (16.6)	45 (28.7)
Orthopedic surgeon	112 (13.3)	45 (11.8)	52 (17.2)	15 (9.6)
Other	13 (1.5)	3 (0.8)	16 (2.0)	4 (2.5)
Physician reported visits, mean (SD) visits/year^c
n	819	377	293	149
All healthcare providers	3.2 (2.73)	2.8 (2.25)	3.5 (2.96)	3.6 (3.24)	0.0013
Primary care physician	2.5 (2.02)	2.1 (1.23)	2.9 (2.61)	2.6 (2.29)	0.0008
Rheumatologist	2.7 (1.52)	2.6 (1.26)	2.8 (1.82)	2.7 (1.45)	0.4815
Orthopedic surgeon	2.2 (1.18)	2.2 (1.20)	2.3 (1.16)	2.1 (1.17)	0.6206
Physical therapist	4.5 (4.20)	3.8 (3.60)	4.4 (2.67)	9.5 (7.19)	0.0348

^aPain intensity was based on pain over the last week using the 11-point Numeric Rating Scale including mild (0–3), moderate (4–6), and severe (7–10) pain categories.

^bVisits to pain specialists, anesthetists, nurse practitioners, physician assistants, neurologists, radiologists, and other physicians were also reported by patients in this survey but are not included here.

^cVisits to pain specialists, anesthetists, nurse practitioners, physician assistants, neurologists, radiologists, and other physicians were also reported by physicians in this survey but are not included here.

^dp-value reflects a difference among severity groups in percentages for categorical outcomes and in means for continuous outcomes.

HCP = healthcare provider; SD = standard deviation.

Table 4. Physician-reported OA-related procedures, ED use, and hospitalizations according to pain severity^a

Reason, n (%)	Patient-reported OA pain severity
	Overall (n = 841)	Mild (n = 382)	Moderate (n = 302)	Severe (n = 157)	p-value^b
Imaging tests for diagnoses
X-ray	731 (86.9)	327 (85.6)	268 (88.7)	136 (86.6)	0.4778
MRI	133 (15.8)	54 (14.1)	53 (17.5)	26 (16.6)	0.4591
CT scan	16 (1.9)	12 (3.1)	2 (0.7)	2 (1.3)	0.0551
Any scan performed	745 (88.6)	331 (86.6)	277 (91.7)	137 (87.3)	0.0989
Imaging tests for monitoring
X-ray	470 (55.9)	184 (48.2)	196 (64.9)	90 (57.3)	< 0.0001
MRI	98 (11.7)	45 (11.8)	33 (10.9)	20 (12.7)	0.8435
CT scan	6 (0.7)	0 (0)	4 (1.3)	2 (1.3)	0.0447
Any scan performed	528 (62.8)	216 (56.5)	210 (69.5)	102 (65.0)	0.0019
ED use over the last 12 months
No	747 (96.5)	360 (97.6)	262 (96.0)	125 (94.7)	0.2547
Yes	27 (3.5)	9 (2.4)	11 (4.0)	7 (5.3)
Hospitalizations over the last 12 months
No	722 (92.8)	350 (95.1)	249 (91.9)	123 (88.5)	0.0281
Yes	56 (7.2)	18 (4.9)	22 (8.1)	16 (11.5)
Reasons for hospitalization
For surgery	44 (78.6)	17 (94.4)	14 (63.6)	13 (81.3)	0.3994
To treat a complication	2 (3.6)	0 (0)	1 (4.5)	1 (6.3)
To treat side-effects associated with OA medication	2 (3.6)	0 (0)	1 (4.5)	1 (6.3)
Other	5 (8.9)	1 (5.6)	3 (13.6)	1 (6.3)
Not known	3 (5.4)	0 (0)	3 (13.6)	0 (0)
Surgery
No surgery	657 (78.1)	319 (83.5)	226 (74.8)	112 (71.3)	0.0043
Surgery in last 12 months	54 (6.4)	20 (5.2)	18 (6.0)	16 (10.2)
Surgery more than 12 months ago	130 (15.5)	43 (11.3)	58 (19.2)	29 (18.5)
Is surgery planned?
No	592 (70.4)	334 (87.4)	175 (57.9)	83 (52.9)	< 0.0001
Yes, in the next 12 months	82 (9.8)	10 (2.6)	33 (10.9)	39 (24.8)
Yes, at longer than 12 months	167 (19.9)	38 (9.9)	94 (31.1)	35 (22.3)

^aPain intensity was based on pain over the last week using the 11-point Numeric Rating Scale including mild (0–3), moderate (4–6), and severe (7–10) pain categories.

^bp-value reflects a difference in percentages among severity groups.

CT = computerized tomography; ED = emergency department; MRI = magnetic resonance imaging; OA = osteoarthritis.

Figure 1. Physician-reported planned surgical procedures^a to be undertaken for OA

^aPlanned surgeries were split into ‘in the next 12 months’ or ‘more than 12 months’ but the current plot combines the two. ^bSignificant differences between groups (p = 0.0481). ^cOther surgery includes lumbar/back surgery and carpal tunnel release surgery. Significant differences between groups (p = 0.0411). Pain intensity was based on pain over the last week using the 11-point Numeric Rating Scale including mild (0–3), moderate (4–6), and severe (7–10) pain categories.

Figure 2. Patient-reported need for support due to OA according to patient-reported pain severity. All comparisons showed significant changes (p < 0.0001). Pain intensity was based on pain over the last week using the 11-point Numeric Rating Scale including mild (0–3), moderate (4–6), and severe (7–10) pain categories

^aMild (n = 355); moderate (n = 286); severe (n = 143). ^bMild (n = 136); moderate (n = 201); severe (n = 116). ^cMild (n = 341); moderate (n = 275); severe (n = 133). ^dMild (n = 343); moderate (n = 283); severe (n = 137). OA = osteoarthritis.

Data availability

Adelphi Real World was responsible for the analyses and house the data.