Ramadan and warfarin: average clotting holds steady, but more readings drift off target
Riyadh clinic records on 114 people with mechanical heart valves point to closer checks during the fasting month.
People with mechanical heart valves take warfarin for life, and their clotting level, measured as the INR, has to stay inside a narrow band. Ramadan changes meal times, sleep and daily routines. Does that upset the balance?
A team in Riyadh, writing in The Ulutas Medical Journal in 2018, looked back at the records of 114 patients from a specialised anticoagulation clinic. Each person's first INR during Ramadan 2015 was compared with their own average over the three months before.
On average, little changed: 2.81 before and 2.75 during the fasting month. But individual readings strayed more often. Among patients with the higher target range, the share on target fell from 64.9% to 51.3%, a difference that did not reach statistical significance.
The authors advise closer INR monitoring for warfarin users who fast.
Caveat: this is a retrospective single-centre analysis that compared just one Ramadan reading per patient with earlier results.
Source: Mohammed Alghamdi et al. Effect of Ramadan Fasting on the International Normalized Ratio in Patients with Mechanical Prosthetic Heart Valves. Ulutas Med J 2018. doi:10.5455/umj.20180117091224.
Image: Figure 2 of the article, CC BY-NC 4.0.
