Efficacy of daily hypertonic saline nasal irrigation among patients with sinusitis: A randomized controlled trial
Randomization
The randomization scheme was prepared by the Investigational Drug Services of the University of Wisconsin Hospital and Clinics. Subjects were stratified by smoking status and then randomized by using an approximate 2:1 block design, with 10 subjects per block. Therefore 68% of subjects were assigned to the experimental group and 32% to the control group. A 2:1 scheme favoring the experimental group was selected due to resource limitations.
Eligibility criteria and subject recruitment
The recruitment and subject participation scheme is shown in Figure W1 (available on the JFP Web site: https://www.jfponline.com). The billing databases for the University of Wisconsin primary care and Ear, Nose, and Throat (ENT) practices were screened for acute and chronic sinusitis (codes 461 and 473, respectively, from the International Classification of Diseases, Ninth Revision). Patients 18 to 65 years old with 2 episodes of acute sinusitis or 1 episode of chronic sinusitis per year for 2 consecutive years (n = 602) were sent a letter explaining the study and inviting participation, along with an opt-out postcard. If no card was returned, potential subjects were phoned. Exclusion criteria included pregnancy and comorbidity significant enough to preclude travel to an informational meeting or performance of the nasal irrigation technique. Patients indicating “moderate to severe” impact of sinus symptoms on their QOL on a Likert scale of 1 to 7 were invited to attend an informational meeting involving enrollment, randomization, and training (n = 128). Of those potential subjects, 44 declined the meeting or were ineligible; 84 agreed to attend the meeting, 77 attended, and 76 enrolled. Of the initial group of 602 potential subjects, 375 were not contacted because the study census reached intended sample size.
One of us (D.R., R.M., or A.Z.) facilitated each informational meeting of 1 to 6 persons. Sealed envelopes containing the patient’s randomized group assignment were distributed to subjects in the order they entered the room. The group assignment was unknown to the investigator. Subjects broke the seal and learned their assignment. Thereafter, investigators were not blind to subjects’ group assignment. Persons managing and analyzing data also saw unblinded data but had no contact with subjects. Participants heard a brief presentation about sinus disease and its treatment. Nasal irrigation theory and technique were explained. Seventy-six subjects consented and were allocated by their randomized group assignments to experimental (n = 52) or control (n = 24) groups. Control subjects continued treatment of sinus disease in their usual manner. Experimental subjects saw a brief demonstration film, witnessed nasal irrigation by the facilitator, and demonstrated proficiency with the nasal irrigation technique before departure. Subjects were provided all ingredients and materials for 6 months of daily nasal irrigation. Experimental subjects also continued usual care for sinus disease.
Intervention
Subjects in the experimental group were asked to irrigate the nose (150 mL through each nostril) daily for 6 months with the SinuCleanse19 nasal cup containing 2.0% saline buffered with baking soda (1 heaping teaspoon of canning salt, one half teaspoon of baking soda, and 1 pint of tap water; (Table 1). Solution was mixed fresh every 1 to 2 days. All subjects were phoned at 2 weeks to assess initial compliance with study protocols and thereafter if assessment instruments were not returned promptly.
TABLE 1
Baseline patient characteristics*
| Variable | Control group (n = 24) | Experimental group (n = 52) |
|---|---|---|
| Age, y† | 41.4 ± 2.4 | 42.4 ± 1.4 |
| RSDI score† | 59.6 ± 3.0 | 58.4 ± 2.0 |
| SF-12 score† | 59.3 ± 4.0 | 60.3 ± 3.0 |
| SIA score† | 4.1 ± 0.2 | 3.9 ± 0.1 |
| Female‡ | 18 (75) | 37 (71) |
| Caucasian race‡ | 23 (96) | 49 (94) |
| Smokers‡ | 1 (4) | 3 (6) |
| Education‡ | ||
| ≤High school | 6 (25) | 11 (21) |
| Some college | 10 (42) | 18 (35) |
| ≥College degree | 8 (33) | 23 (44) |
| Seasonal allergies‡ | 17 (71) | 34 (66) |
| Medication allergies‡ | 12 (50) | 29 (56) |
| ENT history‡ | ||
| Nasal surgery | 7 (29) | 19 (37) |
| Nasal polyps | 3 (13) | 9 (17) |
| Deviated septum | 7 (29) | 12 (23) |
| Nasal fracture | 4 (17) | 7 (13) |
| Asthma‡ | 4 (17) | 14 (27) |
| ICD-9 code‡ | ||
| 461 (acute sinusitis) | 20 (83) | 34 (65) |
| 473 (chronic sinusitis) | 2 (8) | 11 (21) |
| Both (acute and chronic sinusitis) | 2 (8) | 7 (14) |
| Clinic type‡ | ||
| Primary care | 24 (100) | 46 (89) |
| ENT | 0 (0) | 6 (12) |
| *At baseline, there were no statistically significant (P > .05) differences between the experimental and control groups. | ||
| †Data are presented as mean ± standard error. | ||
| ‡Data are presented as number (%) of subjects. | ||
| ENT, Ear, Nose, and Throat; ICD-9, International Classification of Diseases, Ninth Revision; RSDI, Rhinosinusitis Disability Index; SF-12, Medical Outcomes Survey Short Form 12; SIA, Single-Item Symptom Severity Assessment. | ||
Outcome measures
The primary outcomes were QOL scores from 2 validated questionnaires: the general health assessment Medical Outcomes Survey Short Form (SF-12)20 and the RSDI,21 a disease-specific instrument assessing QOL in emotional, functional, and physical domains. We reworded the phrase my problem to my sinus symptoms on several RSDI items. Consensus within the research group and among consulted experts was that this minor change facilitated more accurate reading and reporting. We also measured overall sinus symptom severity with a Single-Item Symptom Severity Assessment (SIA): “Please evaluate the overall severity of your sinus symptoms since you enrolled in the study”; higher scores on the Likert scale SIA indicated increased severity. Scales for RSDI and SF-12 ranged from 0 to 100 points, with higher scores indicating better overall QOL. Each was completed at baseline and at 1.5, 3, and 6 months; at the 6-month assessment, subjects were shown their baseline answers for comparison because they had told us they needed to recall answers to past questions. They believed they knew whether they felt better or worse and wanted their later answers to reflect this change. Allowing subjects to view previous scores is an accepted research practice.22 However, because we did not allow subjects to see their baseline answers at 1.5 and 3 months, scores must be interpreted in light of the availability of the baseline data to the subjects.
