Multi-database study of multiple sclerosis: identification, validation and description of MS patients in two countries

Abstract

Objective To describe the resources and methods used to identify and validate multiple sclerosis (MS) and match non-MS patients in each of the two databases, and to characterize their demographics, comorbidities and concomitant medications. Methods This study was conducted in two separate electronic medical databases, the United States Department of Defense (DOD) military health care system and the United Kingdom’s Clinical Practice Research Datalink (CPRD) GOLD. We identified patients with a first recorded diagnosis of MS in 2001–2016 (CPRD) or 2004–2017 (DOD) and matched non-MS patients using algorithms appropriate to each database. We describe patient symptoms, comorbidities, and medication use at the time of the MS diagnosis and compared them to the non-MS cohort. Results We identified 8695 patients with MS and 86,934 matched non-MS patients in the DOD database and 6932 patients with MS and 68,526 matched non-MS patients in CPRD GOLD. Most MS patients were female (around 70%) and were diagnosed before age 60 (88%). MS patients had higher prevalence of depression and other psychiatric conditions at MS diagnosis compared to non-MS patients. Epilepsy, fractures and infections were also more common. MS patients had many expected symptoms and treatments documented in their records prior to the MS diagnosis. Conclusion These results are consistent between the two databases, as well as with previous studies of MS. Future analyses of these patients’ experience after MS diagnosis will provide valuable insights into disease and treatment patterns in relation to risk of chronic diseases and mortality.

Incident depression in patients diagnosed with multiple sclerosis: a multi‐database study

“…From the overall MS study population described previously [7], patients with prior treated depression were excluded (1875 (21.6%) MS patients from the US‐DOD and 1476 (21.3%) MS patients from the UK‐CPRD). The treated‐depression‐free study population included 6820 (US‐DOD) and 5456 (UK‐CPRD) MS patients matched, respectively, to 58 419 and 45 712 non‐MS patients with no record of treated depression before cohort entry.…”

“…Rates of treated depression may be higher in the US‐DOD due to earlier treatment of depression symptoms in the US population. Because of differences in data availability, MS disease‐modifying treatments were required in the US‐DOD cohort but not for the UK‐CPRD cohort (CPRD GOLD does not have complete capture of biologic treatments administered through infusion or injection) [7]. It is possible that some less severe MS patients were excluded from the US‐DOD analysis and that this US cohort may therefore comprise more severe MS patients compared to the UK cohort.…”

Non-infectious comorbidity in patients with multiple sclerosis: A national cohort study in Sweden

“…With regard to more serious consequences of comorbidity, MS patients experienced both an increased rate of hospitalizations and elevated mortality. Only a few previous population-based studies have focused on incident comorbid conditions in MS, 18,20,29,30 and we could only identify one with reported age- and sex-specific incidence estimates. 20,29,30 In this respect, the present study is the first to contribute evidence of patterns of comorbidity that characterize the period following a diagnosis of MS.…”

“…Despite some progress in recent years, significant knowledge gaps regarding comorbidity in MS remains. In particular, population-based studies focusing on incident conditions in MS are still rare, 18,20,29,30 and only a few published study reporting age- and sex-specific incidence estimates. 20,29,30 The objective of this study was to explore incident comorbidity, mortality and hospitalizations, stratified by age and sex, in a large national, population-based cohort of MS patients in Sweden.…”

Infections in patients with multiple sclerosis: A national cohort study in Sweden

“…Multiple sclerosis (MS) is the major disabling neurological disease affecting young adults (Kobelt et al, 2017). In addition, MS patients experience a higher occurrence of several physical and mental conditions, including acute infections, as compared with the general population (Bazelier et al, 2011;Chou et al, 2020;Jick et al, 2015;Marrie, 2017;Marrie et al, 2015aMarrie et al, , 2015bMarrie et al, , 2015cMurtonen et al, 2018;Patten et al, 2017;Persson et al, 2019Persson et al, , 2020bTettey et al, 2014;Thormann et al, 2016). An increased occurrence of several immune-mediated diseases, such as ulcerative colitis, Crohn's disease, psoriasis, polyarteritis nodosa, and pemphigoid have also been described for Swedish patients with MS; however, surveillance bias may contribute to the observed increase in risk (Roshanisefat et al, 2012).…”