The Tokyo Metropolitan Government has begun investigating a hospital suspected of suggesting to 149 kidney disease patients since 2013 that they not receive dialysis treatment, resulting in the death of at least one female renal patient and decisions by some 20 others to quit, it was learned Thursday.

The patient in her 40s died about a week after signing a letter of consent to end dialytic treatment, after a doctor at Fussa Hospital in western Tokyo explained to her and her family that the decision may result in death, the sources said.

According to guidelines set in 2014 by the Japanese Society for Dialysis Therapy, the termination of hemodialysis should only be considered in specific cases, including when it is difficult to continue the treatment safely and when the treatment itself could elevate the risk of death.