* Shares tank despite robust earnings, outlook

* Patient volumes outlook lower than peer's -analysts

* Few patients on GLP-1s, growth rate very slow -CEO

Feb 20 (Reuters) - Fresenius Medical Care's shares fell 5% on Tuesday, despite upbeat quarterly results and higher 2024 guidance, with analysts highlighting a weak outlook for patient volumes from the German dialysis specialist.

U.S. competitor Da Vita last Tuesday forecast a 2024 outlook above expectations, forecasting patient volumes would increase by 1% to 2% during the year, while FMC targeted growth of 0.5% to 2%, analysts at Barclays said.

The Barclays analysts said that FMC's October-December patient volumes were slightly lower quarter-on-quarter due to missed treatments around Christmas.

FMC said it sees missed treatments partly continuing in the first quarter. "We always expect Q1 to be a bit lower, but that will ramp up during the year," FMC CEO Helen Giza said.

The company's quarterly earnings beat estimates helped by cost cuts and a 175 million euro one-off payment related to a legal settlement in the United States.

"Without this settlement, adjusted earnings would not have grown in FY23. The focus will be on FY24 where expectations were likely higher following DaVita's release last week," JP Morgan analysts said.

GLP-1

Asked about the impact of GLP-1 diabetes and weight-loss drugs on earnings, Giza said this could potentially bring more patients to FMC given they offer cardiovascular protection.

While past trials have shown that GLP-1 drugs could slow the progression of chronic kidney disease, overall survival was also prolonged, potentially keeping patients in FMC's care for longer.

"We do see that this test of drugs is likely to delay the onset to the end-stage renal disease," she added.

Giza said that only about 5% of FMC patients are using GLP-1 drugs, a number that is rising at "a very, very small, small rate." ($1 = 0.9285 euros) (Reporting by Andrey Sychev and Chiara Holzhaeuser in Gdansk; Editing by Milla Nissi, Sherry Jacob-Phillips, David Evans and Alexander Smith)