Table 3.
Included studies that considered the effect of centre in their analyses
| 1st Author and year | Cohort name | Centres (n) | Statistical modelling | Centre modelling | Centre effect |
|---|---|---|---|---|---|
| Albrecht 2015 [19] | CAPEA | 118 | Multivariate logistic regression modelling | Centre included as a fixed effect in regression model | Significant variation in prescribing glucocorticoids at baseline between practice types |
| Harris 2013 [20] | CATCH | 8 | Mixed linear and logistic regression modelling | Centre included as a random effect in regression models | Centre variation in DAS-28 change, remission and therapy choices |
| Lee 2013 [21] | CATCH | 18 | Cox proportional hazards modelling | Stratified by centre | Variation in fibromyalgia diagnoses across centres. Impact on risk estimates not reported |
| Dixey 2004 [22] | ERAS | 9 | Descriptive | Nil | NA |
| Young 2000 [23] | ERAS | 9 | Descriptive | Nil | NA |
| Nikiphorou 2017 [24] | ERAS/ERAN | ERAS 9, ERAN 23 | Mixed effects modelling | Centre included as a random effect in mixed effects models | Not reported |
| Escalas 2012 [25] | ESPOIR | 14 | Mixed effects modelling | Centre included as a random effect in mixed effects models | Adherence to European treatment recommendations associated with a lower risk of radiographic progression, maintained after adjustment for centre |
| Gaujoux-Viala 2017 [26] | ESPOIR | 14 | Multivariate logistic regression modelling | Centre included as a fixed effect in regression model | Optimal MTX treatment associated with higher rates of remission, and maintaining normal function. This was preserved after centre adjustment (unadjusted data not reported) |
| Krams 2016 [27] | ESPOIR | 14 | Multivariate logistic regression modelling | Centre included as a random effect in regression model | Age of onset and steroid dose associated with remission, after centre adjustment. (unadjusted data not reported) |
| Lukas 2011 [28] | ESPOIR | 14 | Multivariate logistic regression and propensity modelling | Centre included in logistic regression model to calculate propensity score | Centre a significant factor in propensity score for predicting treatment choice |
| Lie 2011 [29] | NOR-DMARD | 5 | Multivariate logistic regression and propensity modelling | Centre included in logistic regression model to calculate propensity score | Centre variation in numbers offered combination DMARDs after MTX monotherapy failure |
| Lie 2012 [30] | NOR-DMARD | 5 | Multivariate logistic regression and propensity modelling | Centre included in logistic regression model to calculate propensity score | Wide variation in SSZ prescribing between centres |
| Mueller 2017 [31] | SCQM | ND | Mixed effects modelling | ND | No centre effect observed (data not reported) |
| Jamal 2011 [32] | 15 | Multivariate logistic regression modelling | Centre included as a fixed effect in regression model. Generalized estimating equations performed to investigate for cluster sampling | No intra-centre clustering of results observed (data not reported) | |
| Van der Heijde 1992 [33] | 2 | Multivariate regression modelling | Centre included as fixed effect in regression model | No significant effect on outcomes (data not reported) |
Out of 204 included studies, 15 (7%) accounted for centre effect. Seven included centre as a fixed effect. Six did not report the magnitude of effect, and two described centre level differences. ND: not documented; NA: not applicable; CAPEA: Course And Prognosis of Early Arthritis; CATCH: Canadian Early Arthritis Cohort; ERAN: Early RA Network; ERAS: Early RA Study; ESPOIR: Étude et Suivi des Polyarthrites Indifférenciées Récentes; NOR-DMARD: Norwegian DMARD registry; SCQM: Swiss Clinical Quality Management.