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Whole lung lavage (WLL) is a surgical procedure utilized in China to treat pneumoconiosis, despite the scholarly debate surrounding its efficacy. The National Institute for Occupational Health and Poisoning Control, part of the Chinese Center for Disease Control and Prevention (China CDC), conducted a comprehensive study on pneumoconiosis patients’ health-seeking behaviors across 27 provincial-level administrative divisions (PLADs) over a three-year period, from January 2018 to December 2020. Utilizing baseline data, follow-up patient information, and WLL-related data, a retrospective cohort study was undertaken to evaluate WLL’s impact and gauge the changes in pneumoconiosis-related symptoms and patient quality of life. The study, empowered by propensity score matching (PSM), contrasted 514 patients in both the control and lavage groups. The data illustrated that the patients in the lavage group displayed a marked improvement in expectoration symptoms and self-care than those in the control group. However, this study suggests that while WLL can alleviate some pneumoconiosis symptoms, it offers no significant enhancement to a patient’s overall health status or quality of life.
The present study utilized data from a survey on health-seeking behaviors and a subsequent follow-up survey of pneumoconiosis patients across 27 PLADs in China. The investigation was conducted by the National Institute for Occupational Health and Poisoning Control, affiliated with China CDC (1).
The initial health-seeking behavior survey, undertaken from January 2018 to December 2020, involved studying 9,934 pneumoconiosis patients. Of these, 8,198 valid questionnaires were collected, resulting in a questionnaire recovery rate of 82.5%.
The research group subsequently executed a second telephone follow-up survey from 2020 to 2022. This included the 8,198 pneumoconiosis patients from the initial survey. As of November 2022, follow-up communication had been completed with 5,561 patients. However, the remaining 2,637 patients, who were still being followed up, were not included in the current study due to timing constraints.
The follow-up survey amassed a total of 4,644 valid questionnaires, yielding a questionnaire recovery rate of 83.5%. Tragically, the survey revealed that 232 pneumoconiosis patients passed away during the second follow-up.
The current study finally selected 514 cases, both from the control group (those who had not received WLL treatment prior to the first survey) and the lavage group (those who had received WLL treatment prior to the first survey). A PSM technique was used to match the baseline data from the first survey of 4,412 surviving pneumoconiosis patients with valid questionnaires; 3,322 did not receive WLL before the first survey, and 1,090 received WLL before the first survey (Figure 1).
Figure 1.Flowchart of enrolled patients.
Abbreviation: PSM=propensity score matching.This study utilized PSM to create control and lavage groups from the pool of surveyed pneumoconiosis patients in each medical institution. The final control and lavage groups each included 514 patients. Factors used for matching consisted of gender, age, body mass index (BMI), patients’ source, annual family income, pneumoconiosis stage and type, presence of tuberculosis, self-reported health status, medications for pneumoconiosis, oxygen therapy, and practice of breathing exercises, all of which are crucial influencers on pneumoconiosis patients’ decision to undergo WLL and their overall health condition. The Nearest Neighbor Matching method was applied in a 1∶1 matching ratio with a caliper value of 0.01. The basic information of the two groups of patients is shown in
Supplementary Tables S1 –S2 . The study referenced the European EQ-5D-3L scale to describe patient quality of life. To compare pneumoconiosis-related symptoms and quality of life differences between the two groups, the t-test, chi-squared test or Fisher’s exact probability method was implemented, while paired t-test and paired chi-squared test were used to assess differences between initial and follow-up surveys for both groups. All analyses used SPSS software (version 26.0, SPSS Inc, Chicago, IL, USA). The accepted statistically significant level was set at 0.05 (two-tailed)。Ethical approval for this research was granted by the Ethics Committee of the National Institute for Occupational Health and Poison Control, China CDC (Approval No: 201720). Written informed consent was obtained from all participants.Following PSM, a total of 514 patients were found in each of the control group and the lavage group. The average age in both groups was found to be 53.3 years, with a standard deviation of 9.7 and 8.3, respectively, a difference which was not considered statistically significant (t=−0.052, P=0.959). The average interval between the two surveys was found to be approximately 1.9 years in both groups, with a standard deviation of 0.9 and 0.8, respectively, revealing no significant statistical difference (t=0.799, P=0.424).
In the initial survey, a notable statistical difference was detected regarding expectoration symptoms between the two groups (P<0.001). The percentage of patients exhibiting no expectoration was lower in the lavage group than in the control group (11.7% vs. 19.8%). Conversely, the patient percentage with minimal expectoration was higher than in the control group (62.8% vs. 54.5%). However, in the subsequent follow-up survey, no meaningful difference in expectoration symptoms was found between the groups (P=0.606) (Table 1).
Symptoms The first survey Secondary follow-up survey Control group
n (%)Lavage group
n (%)χ2 P Control group
n (%)Lavage group
n (%)χ2 P Cough 2.079 0.354 4.265 0.119 No 51 (9.9) 38 (7.4) 113 (22.0) 135 (26.3) Mild 310 (60.3) 319 (62.1) 313 (60.9) 310 (60.3) Moderate and severe 153 (29.8) 157 (30.5) 88 (17.1) 69 (13.4) Expectoration 13.959 <0.001 1.003 0.606 No 102 (19.8) 60 (11.7) 166 (32.3) 181 (35.2) Mild 280 (54.5) 323 (62.8) 270 (52.5) 260 (50.6) Moderate and severe 132 (25.7) 131 (25.5) 78 (15.2) 73 (14.2) Chest tightness 2.661 0.264 0.255 0.880 No 64 (12.5) 48 (9.3) 164 (31.9) 157 (30.5) Mild 295 (57.4) 310 (60.3) 258 (50.2) 261 (50.8) Moderate and severe 155 (30.2) 156 (30.4) 92 (17.9) 96 (18.7) Chest pain 5.736 0.057 4.578 0.101 No 199 (38.7) 170 (33.1) 336 (65.4) 329 (64.0) Mild 197 (38.3) 234 (45.5) 118 (23.0) 141 (27.4) Moderate and severe 118 (23.0) 110 (21.4) 60 (11.7) 44 (8.6) Dyspnea 0.439 0.803 4.370 0.112 No 131 (25.5) 129 (25.1) 176 (34.2) 208 (40.5) Mild 222 (43.2) 232 (45.1) 230 (44.7) 212 (41.2) Moderate and severe 161 (31.3) 153 (29.8) 108 (21.0) 94 (18.3) Hemoptysis 0.957 0.328 0.324 0.569 No 460 (89.5) 450 (87.5) 486 (94.6) 490 (95.3) Yes 54 (10.5) 64 (12.5) 28 (5.4) 24 (4.7) Note: The categories for cough severity include mild (intermittent cough not affecting daily activities), moderate, and severe (frequent or violent cough disrupting daily activities and rest). Expectoration is categorized as mild (sputum volume of 10–50 mL during day and night), moderate, and severe (sputum volume exceeding 50 mL during day and night). Chest tightness ranges from mild (intermittent discomfort) to moderate and severe (persistent tightness restricting breathing). Chest pain and dyspnea are classified as mild (occurs during physical activities), moderate, and severe (manifests during daily activities and rest). Table 1. Comparison of pneumoconiosis-related symptoms between the control group and the lavage group — China, 2018–2022 (n=514).
A comparative analysis of pneumoconiosis symptoms before and after the initial and follow-up surveys indicates a significant statistical variation in the severity of the identified eight symptoms across the two groups (P<0.05). We noted a reduction in the proportion of patients in the highest severity level of each symptom and conversely, observed an increased proportion of patients without the said symptoms in both groups (
Supplementary Table S3 ).The initial and subsequent surveys did not reveal any statistically significant disparities in the five elements of self-reported quality of life and health status among pneumoconiosis patients across both groups (P>0.05) (
Supplementary Table S4 ).Upon comparing the quality of life before and after initial and follow-up surveys, no statistically significant changes were observed in the self-care of pneumoconiosis patients from the control group (P=0.083). Conversely, the differences within the lavage group were statistically significant (P<0.001), exemplified by an increased proportion of patients reported to have “no problem” in terms of self-care (Table 2). The average variation in self-reported health status between the two surveys was 9.6±16.7 in the control group and 10.3±18.5 in the lavage group. This difference, however, did not reach statistical significance (t=−0.678, P=0.498).
Quality of life Group Level The first survey Secondary follow-up survey P Mobility, n (%) Control group No problems 302 (58.8) 365 (71.0) <0.001 Moderate problems 206 (40.1) 140 (27.2) Extreme problems 6 (1.2) 9 (1.8) Lavage group No problems 322 (62.6) 388 (75.5) <0.001 Moderate problems 189 (36.8) 123 (23.9) Extreme problems 3 (0.6) 3 (0.6) Self-care, n (%) Control group No problems 405 (78.8) 426 (82.9) 0.083 Moderate problems 106 (20.6) 82 (16.0) Extreme problems 3 (0.6) 6 (1.2) Lavage group No problems 386 (75.1) 442 (86.0) <0.001 Moderate problems 125 (24.3) 70 (13.6) Extreme problems 3 (0.6) 2 (0.4) Usual activities, n (%) Control group No problems 251 (48.8) 317 (61.7) <0.001 Moderate problems 232 (45.1) 173 (33.7) Extreme problems 31 (6.0) 24 (4.7) Lavage group No problems 264 (51.4) 349 (67.9) <0.001 Moderate problems 221 (43.0) 143 (27.8) Extreme problems 29 (5.6) 22 (4.3) Pain/discomfort, n (%) Control group No problems 118 (23.0) 233 (45.3) <0.001 Moderate problems 352 (68.5) 255 (49.6) Extreme problems 44 (8.6) 26 (5.1) Lavage group No problems 147 (28.6) 234 (45.5) <0.001 Moderate problems 330 (64.2) 268 (52.1) Extreme problems 37 (7.2) 12 (2.3) Anxiety/depression, n (%) Control group No problems 219 (42.6) 292 (56.8) <0.001 Moderate problems 214 (41.6) 193 (37.5) Extreme problems 81 (15.8) 29 (5.6) Lavage group No problems 217 (42.2) 313 (60.9) <0.001 Moderate problems 210 (40.9) 176 (34.2) Extreme problems 87 (16.9) 25 (4.9) Health status self-score $(\bar x \pm s )$ Control group / 59.1±17.3 68.7±15.8 <0.001 Lavage group / 59.0±17.2 69.3±16.3 <0.001 Note: “/” means health status self-score did not differentiate levels. Table 2. Comparative analysis of quality-of-life differences between the two patient groups across two surveys — China, 2018–2022 (n=514).
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This research involved the selection of lavage and control groups through PSM for the purpose of comparing differences in pneumoconiosis-related symptoms and quality of life. These two groups of pneumoconiosis patients exhibited similar baseline characteristics, allowing for a preliminary evaluation of the effects of WLL on these patients. The intent was to stimulate thought and inform future empirical studies focusing on the long-term efficacy of WLL for pneumoconiosis patients. The Consensus of Chinese Experts on Pneumoconiosis Treatment (2018) purports that while WLL significantly improves clinical symptoms in the short term, current evidence does not substantiate a marked therapeutic impact on lung function and pulmonary fibrosis. As WLL is an invasive treatment, it is currently not upheld as a standard treatment for pneumoconiosis (2). The results from the study’s initial survey are presented herewith.
The survey data revealed a 17.8% prevalence rate for WLL use among participants, signaling its considerable utilization as a nonstandard treatment technique. Earlier studies typically gauged the efficacy of WLL via self-regulated pre-and post-surgical evaluations, concluding that WLL might have a positive impact on alleviating short-term pneumoconiosis symptoms (3–4). Nonetheless, the present research suggests that both patient groups exhibited improved health status. This improvement may be attributable to recent enhancements in national support policies for individuals with pneumoconiosis and the survivor effect (5–6). Therefore, when assessing WLL’s impact on pneumoconiosis patients, mere self-comparisons before and after the treatment may not accurately reflect the reality of their condition.
In studies involving control groups, the influential confounding factors affecting the health condition of patients with pneumoconiosis were either not adjusted or only a few were accounted for. Despite this, these studies generally concluded that WLL had short-term beneficial effects on the patients’ health (7–8). Before adjusting for confounders, WLL was linked to improvements in numerous respiratory symptoms and quality of life. WLL typically targets patients with relatively mild conditions that are more likely to tolerate the procedure, introducing potential selection bias in the outcomes (9–10). In our study, however, we employed a large sample size and controlled for the principal factors that may influence both the patients’ decision to undergo WLL and their health conditions. Using PSM, we equalized the baseline characteristics of both patient groups. This approach allowed us to evaluate the effects of WLL on pneumoconiosis patients more accurately.
The findings of the study indicate that WLL yielded a moderate effect on alleviating expectoration symptoms when juxtaposed with the control. However, there was no significant improvement in symptoms such as coughing, chest tightness, chest pain, and dyspnea in comparison to the control. This finding is consistent with the underlying mechanism that WLL works by cleansing the respiratory tract and pulmonary sputum of patients with pneumoconiosis, thus aiding those with substantial sputum stasis that is challenging to expectorate. In terms of quality of life assessment, WLL only significantly enhanced the self-care abilities of the pneumoconiosis patients contrasted with the control. However, no notable improvements were evident in the remaining four aspects and the overall health status compared with the control group.
This study indicates that WLL has a modest impact on pneumoconiosis patients and should not be considered a standard treatment. However, this research primarily assessed the influence of whole lung lavage based on patients’ subjective experiences of symptoms and quality of life, without incorporating objective measurements, such as chest imaging and lung function. This omission represents a limitation. Future research on the use of WLL in pneumoconiosis treatment should endeavor to provide stronger evidence by choosing indicators that can objectively assess disease severity, progression, and patient quality of life. It should also account for potential confounding factors, such as the quality of WLL operation, patients’ dust exposure history, medication therapies, and other treatment modalities. A systematic evaluation of WLL’s long-term efficacy using standardized methodologies is recommended to fairly assess WLL’s cost-effectiveness for pneumoconiosis patients.
The current study inadequately addresses the potential influence of varied WLL procedure quality across different medical institutions on patient outcomes. Furthermore, the research does not provide detailed information regarding the dust exposure history and work type of participants, likely influencing the assessed impact of WLL on pneumoconiosis patients. Additionally, potential disparities in data collection methods could introduce bias as the initial questionnaire involved face-to-face interviews, whereas the secondary follow-up predominantly used telephone interviews. Consequently, the potential for information bias is apparent in the comparison of the two surveys’ results.
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No conflicts of interest.
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The participants in the study and the members of the survey teams in each of the 27 regional centers, and the project development and management teams.
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