The 59-year-old woman died on Wednesday at the Edinburgh Royal Infirmary after falling ill at the city's Elsie Inglis nursing home on Monday.
Scotland's social work watchdog has launched an investigation into "serious concerns about the quality of care", while an emergency operation to rehouse other vulnerable residents is under way.
The private home, which charges up to 31,000 per year and is owned by Edinburgh-based Peacock Medicare, has consistently received good reports from the Care Commission in recent years. However, Scotland on Sunday has learned concerns were raised over Medication Administration Records (MAR). During an unannounced inspection on 4 October 2010, Care Commission officer Anne Dolan found that "recording of 'as required' medication in the MAR sheets were not always consistent".
She said: "In one unit 'as required' medications were recorded as the medication was administered. In another unit 'as required' medications were recorded as not being required at each medication round. This was very confusing. This had also been identified at the most recent audit in September 2010."
Records from Social Care and Social Work Improvement Scotland, the newly-established care inspectorate, have revealed that complaints about "language difficulties" between patients and staff and "record keeping" registered on 30 November last year were fully upheld by the body.
A spokesman for the SCSWIS said: "We continue to have serious concerns about the quality of care provided at Elsie Inglis nursing home and are currently considering whether to take enforcement action against the service."
Dr Nawal Bagaria, who runs the home, said: "We are in discussions with SCSWIS and Edinburgh Council and these discussions are still ongoing."