Meeting Abstract MO878. Background and Aims Nephrologists and General Practitioners (GP) are critical in the care trajectory of patients with CKD through the medical work they provide: screening, referral, follow-up, slowing down CKD progression and renal replacement therapy preparation. They often intervene simultaneously in a collaborative context. Several guidelines define this medical work and collaborative care models. However, evidence suggests that the implementation of such models is limited and suboptimal. For example, 18% of patients who started dialysis in 2018 in France did not see a nephrologist before.The objectives of this study were 1) to quantitatively describe the practices of both French nephrologists and GPs through drug and biology lab test prescriptions for patients with CKD and its evolution before and after dialysis start, 2) to qualitatively describe how they see each other’s role and from this 3) identify the factors interfering with optimal care trajectory Method All incident 2015 dialysis patients from France were identified using the national REIN registry. Healthcare consumption of those patients 2 years before and 1 year after dialysis start was retrieved from the French national health insurance database (SNDS) via indirect record linkage. The items of interest were drug and lab test prescriptions as well as the prescriber medical specialty. Prescription frequencies and percentages per months and per prescriber specialty were reported. Anatomical Therapeutic Chemical (ATC) classification level 2 was used for drugs. Semi-structured interviews with general practitioners and nephrologists exploring their practices surrounding CKD care were performed in a sample from the Bretagne region. Thematic analysis was performed on the transcripts. Results A total of 2 263 935 drug prescriptions were found for 8679 patients who started dialysis in 2015 in France in the span of 2 years before and 1 year after dialysis start. The place of each professional changed through time: drug prescribed by GPs decreased from 83.6% of the total during the 2 years before dialysis start to 62.6% during the year following dialysis start. Nephrologist’s place increased from 4.9% of the total prescriptions to 21%. Although GPs and nephrologists had differences between the drugs they prescribe (nephrologists prescribed more frequently vitamins and antianemic preparations whereas GPs prescribed more frequently analgesics and drugs used in diabetes), they also had similarities (frequencies of beta blocking agents, calcium channel blockers and lipid modifying agents). Similarly, the interviews highlighted that despite the unique technical nature of a large part of nephrologists’ practice (nephropathy aetiology, dialysis and kidney transplantation, nephrotoxicity) another part was similar to GPs’, including the long-term holistic care of patients with multiple comorbidities as well as diet and lifestyle advices. This appears to blur the perimeter of the role of each professionals regarding CKD care and favours an increased presence of nephrologists, as suggested by the quantitative prescription analysis. In turn, as interviews revealed, some GPs expressed a fear of losing their patients and regretted a decreased communication from specialists. Nephrologists’ description of the role of GPs ranged from a strict addressor to nephrologists, to an intermediary support to reduce uncertainties, to a constant partner with transfer of therapeutic objectives. Conclusion Combining the crossed point of view of GPs and nephrologists and robust prescription data, this study highlights an overlap in the roles and practices and suggests a competition in the control of therapeutic strategies that might hinder an optimal care trajectory for patients. Development of integrated renal care network could address these obstacles