Centre-Related Variability in Hospital Admissions of Patients with Spondyloarthritis

CENTRE-RELATED VARIABILITY IN HOSPITAL ADMISSIONS OF PATIENTS WITH SPONDYLOARTHRITIS.

-- Appendix –

Section I. Included variables full list

Clinical variables

I. Diseases characteristics

Date of symptoms onset (duration of symptoms attributable to SpA at the first visit in rheumatology), date of first visit to rheumatology, date of diagnosis (when the SpA diagnosis was registered on the patients’ records), inflammatory markers (ESR, CRP), and disease severity and function in the previous two years according to BASDAI and BASFI, respectively.

SpA specific variables: Type of SpA; fulfilment of SpA criteria (Rudwaleit’s inflammatory back pain criteria, the European Spondyloarthropathy Study Group (ESSG) SpA criteria, Amor’s SpA criteria, axial spondylitis Berlin criteria and AS New York criteria); clinical form (axial, peripheral, enthesal, mixed); extra-articular manifestations (uveitis, psoriasis, inflammatory bowel disease) SpA-related complications (lung involvement, cardiovascular involvement, neurological involvement, , renal disease, osteoporosis, amyloidosis).

II. Comorbidities

Diabetes mellitus, hypertension, coronary heart disease, heart failure, stroke, peptic ulcer, chronic kidney disease, liver disease, serious infections, neoplasm, use of anticoagulation therapy.

Non-clinical variables

a) Patient-centred

I. Demographic characteristics: Date of birth, gender, civil status, educational level, place for living, distance to the hospital, work activity, sick leave periods.

b) Hospital-centred

I. Characteristcs of the responsable physician (considered as who signed at least half of the patient visits in rheumatology): Age, gender, medical specialty, post, years of practice, type of practice (public or private).

II. Characteristics of the centre: Location (autonomic region in Spain). Availability of database about admissions, visits, diagnostic tests and primary care visits. Attended population, total beds number, type of population (countryside, urban).

III. Characteristics of the Rheumatology Unit: Patient attending centre (outpatient clinics in hospital and/or outside hospital), number of facultatives in the staff, registrar training, number of registrars per year, number of assigned beds, total of admissions, total of first and consecutive visits, time to first visit. Availability of telephone consults line, nurse clinic and monographic clinics (SpA and early SpA). Drug monitoring system. Taking part in SpA clinical trials.

Section II. List of Spanish hospitals involved in the emAR II study

Hospital / Number of patients enrolled / %
12 de Octubre / 30 / 2.57
Arnau de Vilanova / 30 / 2.57
Barbastro / 30 / 2.57
Bellvitge / 30 / 2.57
Cabueñes / 30 / 2.57
Carlos Haya / 29 / 2.48
Central de Asturias / 30 / 2.57
Complejo Cáceres / 29 / 2.48
Complejo León / 16 / 1.37
El Bierzo / 29 / 2.48
General Castellón / 30 / 2.57
Gral Yagüe / 30 / 2.57
Gregorio Marañón / 22 / 1.88
Guadalajara / 30 / 2.57
Hospital Basurto / 17 / 1.46
Hospital de la Ribera / 30 / 2.57
Hospital Melilla / 30 / 2.57
Joan XXIII / 30 / 2.57
La Paz / 26 / 2.23
La Princesa / 28 / 2.40
Llerena-Zafra / 5 / 0.43
Los Arcos / 25 / 2.14
Miguel Servet / 30 / 2.57
Móstoles / 1 / 0.09
Negrín / 30 / 2.57
Ntra Sra Candelaria / 30 / 2.57
Palencia / 15 / 1.28
Parc Taulí / 30 / 2.57
Príncipe Asturias / 30 / 2.57
Puerta del Mar / 25 / 2.14
Ramón y Cajal / 27 / 2.31
Reina Sofía / 30 / 2.57
Salamanca / 24 / 2.05
San Jorge / 30 / 2.57
Son Dureta / 30 / 2.57
Univ Albacete / 29 / 2.48
Univ Canarias / 19 / 1.63
Univ Getafe / 30 / 2.57
Univ San Carlos / 30 / 2.57
Univ Santiago / 14 / 1.20
Verge de la Cinta / 29 / 2.48
Virgen de las Nieves / 30 / 2.57
Virgen del Rocío / 30 / 2.57
Virgen Valme / 30 / 2.57
Xeral Calde / 9 / 0.77
Total / 1,168 / 100.0

Section III. Clinical and non-clinical variables.

Demographic data / Comorbidities
Age, years, mean (SD) / 50.1 (13.8) / Hypertension, n (%) / 203 (17.4)
Symptoms onset age, years / 30.4 (23.2-39.8) / Diabetes, n (%) / 71 (6.1)
Gender, female (%) / 371 (32.0) / Coronary heart disease, n (%) / 41 (3.5)
Educational level, n (%) / Stroke, n (%) / 13 (1.1)
None / 15 (1.3) / Peptic ulcer, n (%) / 79 (6.8)
Primary school / 127 (11.0) / Neoplasm, n (%) / 39 (3.3)
High school / 89 (7.7) / Chronic kidney disease, n (%) / 24 (2.1)
University / 85 (7.4) / Liver disease, n (%) / 52 (4.4)
Not registered / 852 (72.9) / Infections, n (%) / 55 (4.7)
Distance from hospital, n (%) (n=1,079) / Anticoagulation therapy, n (%) / 24 (2.1)
Same location / 602 (55.8) / Chronic heart failure, n (%) / 17 (1.5)
20 km / 171 (15.8) / Disease characteristics
20-50 km / 204 (18.9) / Spondyloarthritides diagnosis n (%) (n=1,140)
50 km / 103 (9.54) / Ankylosing spondylitis, / 629 (55.2)
Sick leave >50% time, n (%) / 94 (13.5) / Psoriatic arthritis / 253 (22.2)
Responsible Physician characteristics / IBD-associated arthritis / 50 (4.4)
Female, n (%) / 697 (64.1) / Reactive arthritis / 16 (1.4)
Age, years / 47.9 (49-53) / Undifferentiated spondyloarthritis / 184 (16.1)
Years of experience / 22 (11-25) / Classification criteria fulfilment n (%)
Physician categories / Rudwaleit’s / 375 (32.1)
Registrar, n (%) / 3 (0.3) / ESSG / 716 (61.3)
Consultant, n (%) / 818 (74.7) / Amor’s / 643 (55.1)
Section or Division Chief, n (%) / 274 (25.0) / Berlin / 370 (31.7)
Centre and rheumatology unit characteristics / New York / 598 (51.2)
Attended population, people / 340,000 (200,000-474,993) / Not fulfilling any criteria / 101 (8.6)
Urban population %, mean (SD) / 43.0 (18.0-60.0) / Number of fulfilled sets of SpA criteria / 2.0 (1.0-4.0)
Centre beds number / 666 (457-1,023) / HLA-B27 positive, n (%) / 675 (58.8)
Number of consultants in rheumatology staff / 5 (3-9) / Familial background of SpA, n (%) (n=1,128) / 173 (15.3)
Hospitalization bed numbers / 4 (1-5) / Disease duration, months / 105.1 (48.4-192.5)
Patients admissions/year / 80 (20-145) / Clinical involvement, n (%) (n=1,159)
First visits/year / 2,736 (1,381-4,778) / Axial / 465 (40.1)
Time to first visit, months / 1 (1-2) / Peripheral / 137 (11.8)
Number of registrars/year / 1 (1-1) / Enthesitic / 9 (0.8)
Electronic health records, n (%) / 18 (40) / Mixed / 499 (43.0)
Electronic diagnostic techniques, n (%) / 41 (91.1) / Number of extra-articular manifestations / 1.0 (0.0-1.0)
Computer-assisted admission order, n (%) / 3 (6.7) / Extra-articular complications, n (%)
Nurse clinics, n (%) / 19 (42.2) / Uveitis / 227 (19.4)
Telephone consultation, n (%) / 17 (37.8) / Psoriasis / 243 (20.8)
MSK ultrasound in the unit, n (%) / 32 (71.1) / IBD / 70 (6.0)
SpA monographic clinics, n (%) / 14 (31.1) / Lung involvement / 31 (2.6)
Early SpA monographic clinics, n (%) / 14 (31.1) / Cardiovascular involvement / 45 (3.8)
SpA clinical trials participation, n (%) / 23 (51.1) / Neurological involvement / 15 (1.3)
Renal disease / 25 (2.1)
Osteoporosis / 58 (5.0)
Amyloidosis / 1 (0.1)
BASDAI (n=399) / 3.93 (2.25-5.50)
BASFI (n=315) / 4.04 (1.70-5.90)
CRP, mg/dl / 0.8 (0.3-2.2)
ESR, mm/h / 13.5 (7.0-25.0)
TNF-alpha blocker therapy, n (%) / 477 (40.8)

Data expressed as median (P25-P75) unless specified. Dichotomous variables are expressed as n and percentage. N was specified in brackets when data was missing.

SpA: spondyloarthritis; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; BASDAI: Bath Ankylosing Spondylitis Disease Activity Index; BASFI: Bath Ankylosing Spondylitis Functional Index; TNF: tumor necrosis factor; IBD: inflammatory bowel disease; MSK: musculoskeletal.

The following variables showed a proportion of missing data >20%: Educational level, sick leave periods>50%, BASDAI, BASFI.

Section IV. Admission departments of patients with SpA within the study period.

Admission departments (n=248)
Rheumatology / 59 (23.9%)
Orthopaedics / 41 (16.6%)
General Surgery / 22 (8.9%)
Internal Medicine / 20 (8.1%)
Cardiology / 17 (6.9%)
Urology / 17 (6.9%)
Gynaecology / 15 (6.1%)
Digestive Medicine / 11 (4.4%)
Respiratory Medicine / 9 (3.6%)
Ophthalmology / 7 (2.8%)
Otorhinolaryngology / 6 (2.4%)
Neurology / 6 (2.4%)
Haematology / 3 (1.2%)
Emergency Medicine / 3 (1.2%)
Oncology / 2 (0.8%)
Vascular Surgery / 2 (0.8%)
Plastic Surgery / 2 (0.8%)
Allergy / 1 (0.4%)
Cardiovascular Surgery / 1 (0.4%)
Nephrology / 1 (0.4%)
Thoracic Surgery / 1 (0.4%)
Dermatology / 1 (0.4%)
Unknown / 1 (0.4%)

No admissions were reported in the following units: Intensive Care Unit, Neurosurgery, Maxillofacial Surgery, Psychiatry, Geriatrics and Rehabilitation.

Section V. Univariate analysis. Study variables association with the chance of being hospitalized.

Patients’ Demographic data / OR (95% CI) / Comorbidities / OR (95% CI)
Age / 1.028 (1.016-1.040) / Hypertension / 2.563 (1.789-3.673)
Age at symptom onset / 1.020 (1.006-1.035) / Diabetes / 1.883 (1.059-3.348)
Female / 1.070 (0.770-1.488) / Coronary heart disease / 6.472 (3.271-12.806)
Educational level / Stroke / 1.405 (0.282-7.017)
None / 1.000 (reference) / Peptic ulcer / 1.267 (0.709-2.266)
Primary school / 2.901 (0.358-23.513) / Neoplasm / 9.826 (4.702-20.533)
High school / 2.294 (0.274-19.199) / Chronic kidney disease / 5.906 (2.452-14.223)
University / 0.896 (0.096-8.355) / Liver disease / 0.811 (0.355-1.850)
Distance from hospital / Infections / 5.092 (2.823-9.184)
Same location / 1.000 (reference) / Anticoagulation therapy / 3.557 (1.453-8.707)
20 km / 0.786 (0.487-1.268) / Chronic heart failure / 9.866 (3.006-32.381)
20-50 km / 0.786 (0.509-1.213) / Disease characteristics
50 km / 0.813 (0.455-1.451) / Spondyloarthritis diagnosis
Sick leave >50% time / 1.905 (1.089-3.332) / Ankylosing spondylitis / 1.000 (reference)
Responsible Physician characteristics / Psoriatic arthritis / 1.028 (0.685-1.543)
Female / 0.912 (0.647-1.285) / IBD-associated arthritis / 1.820 (0.901-3.678)
Age / 0.984 (0.965-1.004) / Reactive arthritis / 2.844 (0.911-8.875)
Years of experience / 0.985 (0.967-1.004) / Undifferentiated spondyloarthritis / 1.173 (0.756-1.821)
Physician categories / Classification criteria fulfilment
Registrar / 1.000 (reference) / Rudwaleit’s / 0.684 (0.480-0.975)
Consultant / 0.436 (0.039-4.843) / ESSG / 0.682 (0.498-0.933)
Section or Division Head / 0.489 (0.043-5.514) / Amor’s / 0.753 (0.551-1.028)
Centre and rheumatology unit characteristics / Berlin / 0.758 (0.534-1.074)
Attended population, people / 1.000 (1.000-1.000) / New York / 0.814 (0.595-1.112)
Urban population / 1.001 (0.994-1.008) / Patients not fulfilling any SpA criteria / 1.253 (0.750-2.094)
Centre beds number / 1.000 (1.000-1.000) / Number of fulfilled SpA criteria / 0.878 (0.797-0.968)
Number of faculties in rheumatology staff / 0.971 (0.928-1.016) / HLA-B27 positivity / 0.732 (0.500-1.071)
Unit hospitalization beds number / 1.000 (1.000-1.001) / Familial background of SpA / 0.876 (0.525-1.461)
Patients admissions/year / 1.003 (1.001-1.004) / Disease duration / 1.002 (1.000-1.003)
First visits/year / 1.000 (1.000-1.000) / Clinical involvement
Time to first visit / 1.078 (0.933-1.246) / Enthesitic / 1.000 (reference)
Number of registrars/year / 1.108 (0.760-1.616) / Axial / 0.727 (0.148-3.574)
Electronic health records / 1.160 (0.841-1.600) / Peripheral / 0.902 (0.176-4.612)
Electronic diagnostic techniques / 0.735 (0.456-1.187) / Mixed / 0.940 (0.192-4.600)
Computer-assisted admission orders / 1.400 (0.822-2.385) / Number of extra-articular manifestations / 1.207 (1.039-1.402)
Nurse clinics / 0.730 (0.530-1.007) / Extra-articular complications
Telephone consultation / 0.736 (0.528-1.026) / Uveitis / 0.875 (0.584-1.310)
MSK ultrasound in the unit / 0.700 (0.503-0.974) / Psoriasis / 1.174 (0.805-1.711)
SpA monographic clinics / 1.273 (0.920-1.761) / IBD / 2.170 (1.241-3.796)
Early SpA monographic clinics / 1.102 (0.792-1.532) / Lung involvement / 0.954 (0.357-2.552)
SpA clinical trials participation / 0.824 (0.603-1.125) / Cardiovascular involvement / 2.804 (1.408-5.586)
Neurological involvement / 5.173 (1.562-17.127)
Renal disease / 1.499 (0.583-3.853)
Osteoporosis / 1.001 (0.493-2.032)
CRP / 1.038 (1.016-1.060)
ESR / 1.024 (1.014-1.034)
TNF-alpha blocker therapy / 1.352 (0.989-1.849)

OR: odds ratio. CI: confidence interval. For other definitions, see Table 1 footnotes. The variable “amyloidosis” was not included in the analysis as only one case of amyloidosis was reported. BASDAI and BASFI were not included in the bivariate analysis due to significant missing data.