Non-steroidal anti-inflammatory drugs increase urinary neutrophil gelatinase-associated lipocalin in recreational runners

The knowledge and attitudes of South African-based runners regarding the use of analgesics during training and competition

Background

The use of analgesics is prevalent in runners, with the associated potential for serious harm. However, there is limited information regarding runners' knowledge and attitudes towards the use of analgesics in relation to running.

Objectives

To describe South African-based runners' knowledge and attitudes regarding running-related analgesic use.

Methods

This study has a descriptive, cross-sectional design. South African-based runners, over the age of 18 who ran at least one race in the year preceding the study were included in this study. Participants completed an online questionnaire, including sections on demographic information, training and competition history, pain medication use, and knowledge and attitudes regarding running-related analgesic use.

Results

Data from 332 participants were analysed. Attitudes regarding the use of analgesics in relation to running were generally positive; however, knowledge was poor, with only 20% of participants achieving adequate knowledge scores (75% or above). Very few (n=49; 15%) had both adequate knowledge and positive attitudes, with most respondents (n=188; 58%) having inadequate knowledge and negative attitudes. Negative attitudes towards the use of analgesics were found to increase the odds of running-related analgesic use (OR 2.32; 95% CI:1.31-4.11).

Conclusion

Knowledge regarding running-related use of analgesics was inadequate. Despite a lack of knowledge, attitudes were positive. Participants displayed positive attitudes towards safe practice regarding running-related analgesic use, but these did not translate into good practice. Targeted interventions are required to educate runners and improve their knowledge of all the effects associated with running-related analgesic use.

Non-steroidal anti-inflammatory drugs increase urinary neutrophil gelatinase-associated lipocalin in recreational runners

Objectives

To study the effects of running with/without the use of pain killers on urinary neutrophil gelatinase‐associated lipocalin (uNGAL) and other parameters of kidney function in recreational runners.

Methods

Participants of the 10‐ and 21.1‐km Weir Venloop race were enrolled and their urine samples collected before and after the run. Urine dipstick and other conventional tests used to assess kidney function were performed. The presence of ibuprofen, diclofenac, naproxen, and/or paracetamol was assessed by LC‐MS/MS. uNGAL was measured with a two‐step chemiluminescent immunoassay.

Results

NSAIDs/analgesics were detected in urine of 5 (14.4%) 10‐km runners and 13 (28.9%) 21.1‐km runners. Only half‐marathon participants showed significant increases in uNGAL (pre: 11.7 [7.1‐34.3] ng/mL; post: 33.4 [17.4‐50.4] ng/mL; P = .0038). There was a significant effect of NSAID/analgesic use on uNGAL increase (F_{2, 76} = 4.210, P = .004). Post hoc tests revealed that uNGAL increased significantly in runners who tested positive for ibuprofen/naproxen compared to runners who did not use any medications (P = .045) or those who tested positive for paracetamol (P = .033). Running distance had a significant influence on the increase in uNGAL (F_{1, 53} = 4.741, P < .05), specific gravity (F_{1, 60} = 9.231, P < .01), urinary creatinine (F_{1, 61} = 10.574, P < .01), albumin (F_{1, 59} = 4.888, P < .05), and development of hematuria (χ²(4) = 18.44, P = .001).

Conclusions

Running distance and use of ibuprofen/naproxen were identified as risk factors for uNGAL increase in recreational runners.

Changes in Novel AKI Biomarkers after Exercise. A Systematic Review

More than 100 substances have been identified as biomarkers of acute kidney injury. These markers can help to diagnose acute kidney injury (AKI) in its early phase, when the creatinine level is not increased. The two markers most frequently studied in plasma and serum are cystatin C and neutrophil gelatinase-associated lipocalin (NGAL). The former is a marker of kidney function and the latter is a marker of kidney damage. Some other promising serum markers, such as osteopontin and netrin-1, have also been proposed and studied. The list of promising urinary markers is much longer and includes cystatin C, NGAL, kidney injury molecule-1 (KIM-1), liver-type fatty-acid-binding protein (L-FABP), interleukin 18, insulin-like growth factor binding protein 7 (IGFBP-7), tissue inhibitor of metalloproteinases-2 (TIMP-2) and many others. Although these markers are increased in urine for no longer than a few hours after nephrotoxic agent action, they are not widely used in clinical practice. Only combined IGFBP-7/TIMP-2 measurement was approved in some countries as a marker of AKI. Several studies have shown that the levels of urinary AKI biomarkers are increased after physical exercise. This systematic review focuses on studies concerning changes in new AKI biomarkers in healthy adults after single exercise. Twenty-seven papers were identified and analyzed in this review. The interpretation of results from different studies was difficult because of the variety of study groups, designs and methodology. The most convincing data concern cystatin C. There is evidence that cystatin C is a better indicator of glomerular filtration rate (GFR) in athletes after exercise than creatinine and also at rest in athletes with a lean mass lower or higher than average. Serum and plasma NGAL are increased after prolonged exercise, but the level also depends on inflammation and hypoxia; therefore, it seems that in physical exercise, it is too sensitive for AKI diagnosis. It may, however, help to diagnose subclinical kidney injury, e.g., in rhabdomyolysis. Urinary biomarkers are increased after many types of exercise. Increases in NGAL, KIM-1, cystatin-C, L-FABP and interleukin 18 are common, but the levels of most urinary AKI biomarkers decrease rapidly after exercise. The importance of this short-term increase in AKI biomarkers after exercise is doubtful. It is not clear if it is a sign of mild kidney injury or physiological metabolic adaptation to exercise.