Is incentive spirometry beneficial for patients with lung cancer receiving video-assisted thoracic surgery?

The government implemented the mandatory National Health Insurance (NHI) program in 1995, which covers 99% of the residents in Taiwan [19]. We analyzed the data for this study from the Longitudinal Health Insurance Database for Catastrophic Illness Patients (LHID-CIP) of the National Health Insurance Research Database (NHIRD) established by the National Health Insurance Administration (NHIA, formerly Bureau of National Health Insurance). The data in the LHID-CIP were derived from a sub-data set of the NHIRD that comprised one million randomly sampled beneficiaries enrolled in the NHI program in 2012 and contained all the records on these insurants from 1996 to 2012. Personal identification in NHIRD was recorded before release to researchers. LHID-CIP included all medical claims of each catastrophic illness patient, who suffered from malignancy, autoimmune disorders, and other catastrophic diseases. For validation, the catastrophic illness is based on the clinical report and review of 2 specialists under the NHIA guideline [19]. Diseases were defined in NHIRD according to the International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM). This study was approved by the institutional review board of China Medical University in central Taiwan (CMUH104-REC2–115). Previous studies have indicated a high accuracy of the ICD-9-CM diagnoses in the NHIRD [20, 21].

We identified 66,297 patients with a new diagnosis of lung cancer (ICD-9-CM code 162) in the LHID-CIP from 2000 to 2008. Inclusion criteria included patients newly diagnosed with lung cancers who underwent surgical resection by VATS or thoracotomy. Index date was defined as the date of surgical resection by thoracotomy or VATS. We excluded 58,748 patients with lung cancers, who did not receive surgical resection (Fig. 1).

AARC Clinical Practice Guidelines did not comment on the use of IS in patients following thoracic surgery. The chest surgeons encouraged early mobility and ambulation for patients following thoracic surgery in Taiwan. In addition, some of the chest surgeons prescribed IS for patients with lung cancers receiving surgical resection via VATS or thoracotomy, although this is outside the clinical guidelines. We defined exposure variable as the use of IS (procedure code 57011B) within 7 days of admission for surgical resection by VATS or thoracotomy due to Health insurance payment limited within 7 days after surgery [22] and IS showed a good correlation with vital capacity (VC) in the first 8 days after surgery [23]. The Taiwan National Health Insurance Administration (NHIA) requested the respiratory therapist to conduct IS and reimbursed by the procedure code 57011B. Therefore, the respiratory therapists have to instruct the patient to use IS and follow up the performance [22].The respiratory therapist instructed the IS use in accordance with AARC clinical practice guideline incentive spirometry and recorded in the medical chart for administrative review [14, 24]. The NHIA supervises the medical records routinely by administrative and peer review. The respiratory therapist instructed patients to take slow and deep breaths using the spirometer and hold their breaths for a minimum of 3 s. Patients performed incentive spirometer with 5 to 10 sustained maximal inspiratory maneuvers each hour.

We evaluated the effect of IS in patients admitted with lung cancer receiving surgical resection by VATS or thoracotomy. Primary outcomes included hospitalization cost, incidence of pneumonia (ICD-9-CM codes 481–486), acute respiratory distress syndrome (ARDS, ICD-9-CM code 518.82), and length of stay during the surgical admission. Furthermore, the patient owned the device of IS when they trained to use the IS. The patients were instructed to train the IS in addition to deep breathing and cough training after discharge. Therefore, Secondary outcomes included the frequency of emergency department (ED) visits and the frequency of hospitalizations during serial follow-up periods. The follow-up periods were classified as short-term (3-m), intermediate-term (6-m), and long-term (12-m).

We categorized age into 4 groups: < 55 years, 55–64 years, 65–74 years, and > 75 years. Comorbidities included chronic obstructive pulmonary disease (COPD, ICD-9-CM codes 491, 492, 496) and asthma (ICD-9-CM code 493), heart failure (ICD-9-CM code 428), and other cancer (ICD-9-CM codes 140–208 except 162). In addition, we also collected neoadjuvant therapy (radiation and chemotherapy) and the extent of surgery including pneumonectomy (procedure code 32.5), lobectomy (procedure codes 32.3 and 32.4), and limited resection (procedure code 32.29).

Distribution of demographics (including sex and age groups) and comorbidities (including COPD, asthma, and other cancer) between IS and non-IS groups in patients with lung cancers undergoing VATS or thoracotomy were compared using Chi-square test. Mean ages were measured and compared using student’s t-test. Multivariate linear regression was used to estimate hospitalization cost, length of stay, ED visit frequency, and hospitalization frequency between IS and non-IS groups after controlling for potential covariates. Multivariate logistic regression was used to evaluate the risk of pneumonia and ARDS between IS and non-IS groups after controlling for potential covariates and presented with odds ratios (ORs) and 95% confidence intervals (CIs). Statistical analysis was performed using SAS version 9.4 (SAS Institute Inc., Cary, NC, USA). The statistical significance level was set at 0.05.