Background/Purpose: NSAID is widely used in patients with chronic musculoskeletal pain, but often deteriorates renal function with acute decline of estimated glomerular filtration rate (eGFR). However, there is little evidence on the long-term effect of chronic NSAID use, whether the eGFR decline is irreversible or not.
Methods: We studied 100 patients with chronic musculoskeletal pain (age 66.8 ± 18.4 years; 29 men, 71 women; 46 patients with lumbago, 28 with osteoarthritis, 26 with other complaints) over a followup period of 2 years. The baseline eGFR of the 100 patients was 85.13±25.63 mL/min/1.73m². We compared eGFR change during the first year with daily NSAID administration and that during the following year with daily administration of tramadol hydrochloride/acetaminophen tablets, in the same patient. eGFR was calculated as follows; male,194*Scr�O-1.094*age�O-0.287; female: eGFR (male)*0.739. As for the NSAID during the first year, meloxicam was administered in 33 patients, loxoprofen in 29, diclofenac in 19, and celecoxib in 11.

Results: eGFR change was -0.973 mL/min/1.73m² during the first year with NSAID administration, whereas it was +0.047 mL/min/1.73m² during the following year with tramadol hydrochloride/acetaminophen tablets administration. The difference of eGFR change between the two medications was statistically significant (paired t test, p=0.002; Figure), suggesting the cessation of NSAID and switching to tramadol hydrochloride/acetaminophen tablets can improve the renal function deteriorated by NSAID. As for the specific NSAIDs during the first year, cessation of diclofenac and meloxicam followed by switching to tramadol hydrochloride/acetaminophen tablets resulted in a significant improvement in eGFR (paired t test, p=0.0008 and p<0.0001, respectively; Figure), whereas switching from loxoprofen just showed a tendency of improvement (paired t test, p=0.0604; Figure). On the other hand, cessation of celecoxib and switching to tramadol hydrochloride/acetaminophen tablets did not show significant improvement in eGFR (paired t test, p=0.9389; Figure). Improvement of eGFR after switching to tramadol hydrochloride/acetaminophen tablets was also recognized in 4 patients with diabetes and 12 patients with intake of angiotensin receptor blockers, but did not reach statistical significance. There was no correlation between age and eGFR change over the one year either with NSAID or with tramadol hydrochloride/acetaminophen tablets.

Conclusion: Our findings suggest that reduced eGFR due to one year administration of NSAID could be reversible to a certain degree by cessation of NSAID and switching to tramadol hydrochloride/acetaminophen tablets. The degree of eGFR improvement was different depending on the types of NSAID.