BACKGROUND: Hyperuricemia is a recognised risk factor for cardiorenal complications in hypertensive patients. While prior studies have documented pandemic-related metabolic changes including shifts in serum uric acid (SUA) levels, no study has formally evaluated whether the post-pandemic period modifies the association between hyperuricemia and cardiorenal complication risk - that is, whether hyperuricemia and the post-pandemic period interact synergistically on cardiorenal outcomes beyond their independent effects. This interaction, assessed on both multiplicative and additive scales, remains unexamined. METHODS: We conducted a retrospective cross-sectional study at Pu'er City Hospital of Traditional Chinese Medicine, comparing two non-overlapping periods: pre-pandemic (January 2017-December 2019) and post-pandemic (January 2023-March 2025). After applying predefined exclusion criteria, 3,036 hypertensive adults were included (pre-pandemic: n = 1,482; post-pandemic: n = 1,554). Hyperuricemia was defined as SUA >420 μmol/L in both men and women, in accordance with the 2019 Chinese guideline. The primary outcome was any cardiorenal complication (chronic kidney disease, heart failure, stroke, or atrial fibrillation). Fully adjusted logistic regression models were fitted, and interaction between study period and hyperuricemia was assessed on both multiplicative and additive scales, with the latter quantified using the relative excess risk due to interaction (RERI), attributable proportion (AP), and synergy index (S). RESULTS: Post-pandemic patients had significantly higher mean SUA levels (448.70 ± 72.04 vs 422.39 ± 71.92 μmol/L; P < 0.001) and a higher prevalence of hyperuricemia (65.9% vs 52.1%; P < 0.001). The overall prevalence of any cardiorenal complication was also higher in the post-pandemic group (74.1% vs 49.1%; P < 0.001). In the fully adjusted multiplicative interaction model, hyperuricemia was independently associated with any cardiorenal complication (OR = 1.82, 95% CI: 1.39-2.39; P < 0.001), as was the post-pandemic period (OR = 1.94, 95% CI: 1.50-2.50; P < 0.001). A significant multiplicative interaction was observed between study period and hyperuricemia (interaction OR = 1.79, 95% CI: 1.27-2.53; P = 0.001). Although additive interaction measures were directionally consistent with positive synergism (RERI = 0.155; AP = 0.070; S = 1.149), the bootstrap confidence intervals included the null, indicating that evidence for additive interaction was not statistically conclusive. Findings were consistent across age and sex subgroups and across all six pre-specified sensitivity analyses. CONCLUSIONS: In this hospital-based hypertensive cohort, the post-pandemic period was associated with higher SUA levels and greater cardiorenal complication prevalence. Hyperuricemia and the post-pandemic period showed a significant multiplicative interaction on cardiorenal risk, with directionally consistent but statistically inconclusive additive synergism. These findings support routine SUA monitoring and proactive urate management in the post-pandemic care of hypertensive patients.