The natural history of primary progressive multiple sclerosis: insights from the German NeuroTransData registry
Authors: Braune Stefan , Bluemich Sandra , Bruns Carola , Dirks Petra , Hoffmann Jeanette , Heer Yanic , Rouzic Erwan Muros-Le , Bergmann Arnfin ,   NTD Study Group, Albrecht Walter , Bischof Felix , Bittkau Foroogh , Bittkau Simon , Bohr Kin-Arno , Borries Bettina , Brockmeier Bernd , Brummer Dagmar , Bühler Bernhard , Butz Wolfgang , Cepek Lukas , Claassen Lars , Dee Jürgen , Dieterle Lienhard , Drees Eckehard , Engelmann Christoph , Ernst Michael , Fasold Oliver , Fischer Johannes , Flach Michael , Fleischer Robert , Friedrich Lea , Friedrich Anke , Fritzinger Michael , Gehring Klaus , Gierer Stephanie , Gierer Stephan , Gößling Jens , Grips Eva , Haldenwanger Andreas Hans-Joachim , Harth Andreas , Hartmann Rolf , Helm Roland , Herbst Heinz-Peter , Hofer Christian , Hofmann Werner Erwin , Hoge Alexander , Hummel Sibylla , Ikenberg Benno , Israel-Willner Heike , Jankovits Ralf , Kallmann Boris-Alexander , Kausch Ulrich , Keppler Marc , Kessler Kirn , Kirchhöfer Ulrike , Kirchmeier Jürgen , Knoblich Rupert , Knoll Thomas , Knorn Philipp , Köchling Monika , Kornhuber Anselm Wolfgang , Kramer Bernd , Krause Michaela , Krauß Martin , Kubalek Ralf , Kunz Jürgen , Landefeld Harald , Lange Thomas , Lehmann-Horn Klaus , Lippert Esther , Lippmann Karla , Maier-Janson Walter , Märkl Martin , Masri Said , Moser Christof , Neusch Clemens , Niemann Julius , Paschke Tilmann , Peikert Anna Sybilla , Peikert Andreas , Peters Henning , Pfister Robert , Reifschneider Gerd , Ries Stefan , Rieth Christoph , Roick Holger , Roth Gerhard Dieter , Roth Roland , Safavi Ali , Saur Joachim , Schmitt-Roth Brigitte , Scholz Erich Franz , Schreiber Herbert , Schreiber Klaus , Schrey Christoph , Schumann Carsten , Seiler Martin , Sigel Karl-Otto , Sikora Viola , Sotiriadis Nikolaos , Spiegel Stefanie , Städt Detlef , Sühnel Torsten , Tiel-Wilck Klaus , Ulzheimer Jochen Christoph , Unsorg Barbara Sofie , Voith Silvia , Wannenmacher Achim Stephan , Weber Hildegund , Weih Markus , Wendtland Bernd , Wiborg Andreas , Wimmer Martin , Winker Thomas , Wontroba Isaak , Wüstenhagen Monika 
Published: July 2023

Abstract
Background
Primary progressive multiple sclerosis (PPMS) is characterised by gradual worsening of disability from symptom onset. Knowledge about the natural course of PPMS remains limited.

Methods
PPMS patients from the German NeuroTransData (NTD) MS registry with data from 56 outpatient practices were employed for retrospective cross-sectional and longitudinal analyses. The cross-sectional analysis included a contemporary PPMS cohort with a documented visit within the last 2 years before index date (1 Jan 2021). The longitudinal analysis included a disease modifying therapy (DMT)-naïve population and focused on the evolution of expanded disability status scale (EDSS) from the first available assessment at or after diagnosis within the NTD registry to index date. Outcome measures were estimated median time from first EDSS assessment to first 24-week confirmed EDSS ≥ 4 and ≥ 7. Besides EDSS change, the proportion of patients on disability pension were described over time.

Results
The cross-sectional analysis included 481 PPMS patients (59.9% female, mean [standard deviation, SD] age 60.5 [11.5] years, mean [SD] EDSS 4.9 [2.1]). Estimated median time from first EDSS assessment after diagnosis to reach 24-week confirmed EDSS ≥ 4 for DMT-naïve patients was 6.9 years. Median time to EDSS ≥ 7 was 9.7 years for 25% of the population. Over a decade mean (SD) EDSS scores increased from 4.6 (2.1) to 5.7 (2.0); the proportion of patients on disability pension increased from 18.9% to 33.3%.

Conclusions
This study provides first insights into the German NTD real-world cohort of PPMS patients. Findings confirm the steadily deteriorating course of PPMS accompanied by increasingly limited quality of life.