The causal role of plasma protein ratios in ulcerative colitis: insights from mendelian randomization and single-cell sequencing.

Methamphetamine-associated pulmonary arterial hypertension (Meth-PAH) is increasingly recognized, particularly in Western countries where stimulant use has risen substantially. However, Meth-PAH has not been formally characterized in any Japanese cohorts, so this is the first reported systematic case series of Meth-PAH from a Japanese pulmonary hypertension referral center. We retrospectively reviewed consecutive patients diagnosed with PAH between January 2000 and May 2025. PAH was defined by right heart catheterization as mean pulmonary arterial pressure >20 mmHg, pulmonary arterial wedge pressure ≤15 mmHg, and pulmonary vascular resistance >2 Wood units. Meth-PAH was defined as documented methamphetamine exposure without other identifiable causes of pulmonary hypertension. Clinical and hemodynamic data were extracted. Clinical severity was assessed according to the 4-strata risk assessment recommended by current guidelines.