Colchicine neuromyopathy is usually recognized late, after weakness is already clinically obvious or CK has risen substantially. I hypothesize that in colchicine-exposed patients with eGFR <45 mL/min/1.73 m², a time-updated model combining proximal-weakness onset, weekly CK slope, and concurrent statin exposure will outperform any single absolute CK cutoff for early detection of clinically important colchicine neuromyotoxicity.

Why this is plausible

• Colchicine toxicity is amplified by impaired renal clearance and prolonged exposure.
• Case-series literature repeatedly describes a syndrome of proximal weakness, CK elevation, and neuropathic findings, but the temporal pattern is under-validated.
• CK alone is noisy: some patients present before major CK elevation, while others have competing causes of hyperCKemia.

Testable prediction

In a prospective autoimmune/gout cohort receiving colchicine, a joint model with: (1) new proximal weakness, (2) CK slope over 7-14 days, (3) eGFR category, and (4) statin co-exposure will show higher AUROC and better net benefit for early neuromyotoxicity detection than any rule based on absolute CK alone.

Proposed validation design

• Population: adults exposed to colchicine for gout, CPPD, pericarditis, or autoinflammatory disease.
• Outcome: adjudicated colchicine neuromyotoxicity requiring drug discontinuation.
• Analysis: time-updated logistic/survival model with internal bootstrap validation and decision-curve analysis.
• Falsification: if CK-threshold-only rules perform equivalently or better, the hypothesis fails.

Key references

1. Kuncl RW, Duncan G, Watson D, et al. Colchicine myopathy and neuropathy. N Engl J Med. 1987;316(25):1562-1568. DOI: 10.1056/NEJM198706183162503
2. Wilbur K, Makowsky M. Colchicine myotoxicity: case reports and literature review. Pharmacotherapy. 2004;24(12):1784-1792. DOI: 10.1592/phco.24.17.1784.52342
3. Slobodnick A, Shah B, Krasnokutsky S, Pillinger MH. Colchicine: old and new. Am J Med. 2015;128(5):461-470. DOI: 10.1016/j.amjmed.2014.12.010

Limitations

This may fail if colchicine neuromyopathy is too rare for stable temporal modeling or if CK trajectories are dominated by confounding from statins, inflammatory myositis, or acute illness.