Association between uncertainty regarding malignant risk and anxiety in patients with pulmonary nodules: a serial mediation analysis of illness perception and rumination

Objective This study examined the relationship between uncertainty regarding the risk of malignancy after pulmonary nodule detection and anxiety, and the serial indirect effects of illness perception and ruminative thinking. Methods A total of 308 patients with pulmonary nodules who were admitted to our hospital between January 2023 and January 2026 were included in the study. General information was collected, and participants were assessed using the MUIS, BBIPQ, RRS, and the Chinese version of the GAD-7. Correlation and serial indirect effect analyses were performed using SPSS 26.0 and the PROCESS macro (Model 6). Bootstrap resampling with 5,000 samples was used to assess the stability of indirect effects. Results Among the 308 patients with pulmonary nodules, the MUIS scores ranged from 24 to 86, with a mean of 56.10 ± 12.21. The BIPQ scores ranged 3 to76, with a mean of 43.26 ± 10.67, the RRS scores ranged from 22 to 72, with a mean of 44.66 ± 10.60, and the GAD-7 scores ranged from 1 to16, with a mean of 8.84 ± 2.62. No significant differences in GAD-7 scores were observed among patients with different demographic or disease characteristics ( P >0.05). Pearson’s correlation analysis showed that MUIS scores were positively correlated with BIPQ, RRS and GAD-7 scores ( r = 0.687, 0.577, and 0.745, P < 0.05). BIPQ score was positively correlated with RRS and GAD-7 score ( r = 0.577; 0.601, P < 0.05). RRS score was positively correlated with GAD-7 score ( r = 0.574, P < 0.05). The MUIS had a significant direct effect on GAD-7, accounting for 75.63% of the total effect. The indirect effect consists of three paths: ① MUIS → RRS → GAD-7, with an indirect effect of 0.014, accounting for 8.75% of the total effect; ② MUIS → BIPQ → GAD-7, with an indirect effect of 0.016, accounting for 10.00% of the total effect; and ③ MUIS → BIPQ → RRS → GAD-7, with an indirect effect of 0.009, accounting for 5.62% of the total effect. Conclusion After pulmonary nodule detection, uncertainty regarding the risk of malignancy is positively associated with anxiety, partly explained by the serial indirect effects of illness perception and ruminative thinking, consistent with the hypothesized model.