Understanding Research Paper Differences
This study enrolled 144 CLL (chronic lymphocytic leukemia) patients ("total patient group"). They further grouped these patients into 3 groups according to the treatment they were receiving.

When they refer to "general population" they are referring to norm scores:


  For each patient, an individual norm score was
  derived from age- and gender-matched scores of the general population on the EQ-5D [28] and EORTC QLQ-C30
  [29]. These two studies, as reported in Refs. [28] and [29],
  used a panel consisting of more than 2000 Dutch households, representative of the Dutch-speaking non-institutionalised population in the Netherlands.


So these scores are not part of the current study, but they are estimates from a survey of the wider population rather than patients who have CLL (you can assume they do not have CLL). "Total population" doesn't mean "all CLL", it means "all Dutch-speaking non-institutionalized people".