Impact of Topical Steroid Nasal Irrigation Adherence on Chronic Rhinosinusitis and Allergic Rhinitis Patient Outcomes

ABSTRACT

Objective

High volume steroid nasal rinses are often prescribed for chronic rhinosinusitis and allergic rhinitis. Although the general importance of medication adherence is well established, the specific relationship between objectively measured adherence to topical steroid irrigation and patient‐reported clinical outcomes has not been previously demonstrated. This study aims to investigate the effect of topical steroid nasal rinse adherence on patient outcomes.

Methods

This prospective longitudinal study recruited 97 patients with chronic rhinosinusitis or allergic rhinitis. All patients were prescribed twice‐daily high‐volume budesonide isotonic saline sinus rinses. Objective adherence data through quantified medication usage were collected over 8 weeks. Patient outcomes were assessed via the 22‐item Sino‐Nasal Outcome Test (SNOT‐22), a sinus discomfort visual analog scale (VAS, 0–100), and patient‐perceived surgery need. Generalized estimating equations were used to analyze the impact of adherence on symptom outcomes.

Results

Higher adherence was significantly associated with improvement in both VAS (β = −0.18, p < 0.001) and SNOT‐22 (β = −0.10, p = 0.024) but was not associated with increased surgery desire. Median adherence was overall 47.5%, higher in patients with recent sinus surgery (< 3 months: 55.6%) and higher baseline symptom severity (SNOT‐22 ≥ 20: 51.6%), with correspondingly larger improvements in clinical outcomes.

Conclusion

Objective adherence to budesonide sinus irrigation significantly associates with improved patient‐reported outcomes, with the strongest benefit seen in patients with higher baseline symptoms and in the early postoperative period. Targeting adherence interventions may yield clinically meaningful improvements in sinonasal quality of life.

Level of Evidence

2.

This prospective study of 80 patients with chronic rhinosinusitis or allergic rhinitis used ampule‐count verification, rather than self‐report, to objectively measure adherence to budesonide nasal irrigations and demonstrate a dose–response association with improved SNOT‐22 and VAS scores. The strongest benefit was seen in patients within 3 months of endoscopic sinus surgery and in those with moderate‐to‐severe baseline symptoms.

1. Introduction

Medication adherence directly affects therapeutic success and patient outcomes [1, 2]. While higher adherence generally correlates with improved therapeutic effects, the impact of adherence variability differs across medications [3]. In the field of rhinology, chronic rhinosinusitis (CRS) and allergic rhinitis (AR) are among the most common chronic inflammatory conditions, affecting 12.3% of the general population in the United States [4]. Typical symptoms include nasal congestion, purulent nasal discharge, facial pain or pressure, and reduced quality of life. As part of the standard treatment regimen, topical intranasal steroids have been shown to reduce mucosal inflammation and alleviate rhinosinusitis and associated symptoms [5, 6], especially in individuals who have recently undergone endoscopic sinus surgery [7]. We previously investigated factors influencing adherence to topical intranasal steroids and found that adherence rates varied greatly, with a mean of 45.4% which declined over time [8]. Building on those findings, this present study aimed to investigate the effects of adherence on patients' clinical outcomes using verified ampule‐count, objective adherence rather than self‐reported.

Prior studies have demonstrated low adherence to intranasal corticosteroid therapy in CRS and suggested associations with patient‐reported outcomes, though these investigations primarily relied on self‐reported adherence measures [2, 9]. The relationship between objectively quantified adherence to high‐volume budesonide irrigations and longitudinal sinonasal symptom outcomes has not been well characterized [10]. Existing studies have mostly relied on self‐reported adherence, which can be subjected to recall bias and therefore might not most accurately represent adherence and outcomes. Objective counting can more accurately assess the association between adherence and outcomes to help design adherence‐focused interventions in rhinology in the future.

The primary objective of this study was to assess adherence to high volume topical nasal steroid irrigation and evaluate its relationship with objective and patient‐reported outcomes. A secondary objective was to determine whether patient clinical characteristics influence medication adherence. These findings may help providers understand the clinical impact of medication adherence and the challenges in its implementation.

2. Materials and Methods

2.1. Study Design and Population

A prospective, longitudinal observational study was conducted at a tertiary rhinology clinic at an academic hospital between November 2023 and March 2025. Patients were eligible if they had allergic rhinitis or chronic rhinosinusitis (with or without nasal polyps) according to International Consensus Statement on Allergy and Rhinology (ICAR) guidelines [11] and recommended treatment with topical steroid nasal irrigation. Exclusion criteria included contraindications to corticosteroid therapy, concurrent systemic corticosteroid use, lack of medication insurance coverage, and inability to complete study procedures (e.g., due to language barrier). Demographic and clinical data collected at baseline included prior sinus surgery status, age, sex, race, and comorbidities such as diabetes and asthma. For subgroup analyses, recent surgery was classified as imaging‐guided endoscopic sinus surgery performed within 3 months of study enrollment, and participants who did not receive sinus surgery within this window were classified as no recent surgery. Surgical procedures ranged from full house endoscopic sinus surgery with Draf IIa to extended frontal sinusotomy procedures depending on disease severity and anatomy. All participants were prescribed 0.5 mg/2 mL ampules of budesonide to be mixed with 240 mL isotonic saline and commercial saline packet using NeilMed sinus rinse bottle for twice‐daily high‐volume nasal irrigations. All participants received standardized written and verbal instructions consistent with routine clinical practice. Patients were followed biweekly over an 8‐week period, and those who completed at least one follow‐up assessment were included in the analytic cohort. The study protocol was approved by the University of California San Diego Institutional Review Board (IRB #800066). All participants provided informed consent before enrollment.

2.2. Data Collection

Participants were monitored for 8 weeks from enrollment, with data collected at baseline and biweekly thereafter through telephone interviews or in‐person clinical visits. This follow‐up duration was selected to minimize confounding from disease fluctuation and postoperative recovery effects if applied while maximizing participant response rate. Medication adherence was objectively assessed by counting used budesonide ampules, minimizing recall bias. As patients were instructed to irrigate twice daily, adherence at each interval was calculated as # of ampules used divided by two times the number of days since the last assessment. Overall adherence was averaged across all follow‐ups.

The primary outcomes measure was patient reported sinonasal‐related quality of life score, 22‐item Sinonasal Outcome Test (SNOT‐22) [12]. Secondary outcome measures included sinus discomfort visual analog scale (VAS, 0 = no discomfort, 100 = worst possible discomfort), and an assessment of participants' perceived need for sinus surgery (1. No, no need for surgery; 2. No, had surgery in past 3 months; 3. Yes, but no plan; 4. Yes, surgery decided; 5. I don't know).

2.3. Statistical Analysis

Generalized estimating equations (GEE) were used to analyze the association between adherence and symptom outcomes using the identity link and assess the relationship between adherence and dichotomized symptom burden (SNOT‐22 ≥ 20) using the logit link, accounting for repeated measures within patients [13]. Surgery desire level was analyzed as a nominal outcome. Prespecified subgroup analysis included patients with recent surgery to examine the adherence in the early post‐surgical period. Cohorts with baseline SNOT‐22 ≥ 20 versus < 20 were compared to determine whether initial symptom modified the association between adherence and outcomes. Adherence percentages were compared using the Mann–Whitney U test. A two‐sided p value < 0.05 was considered statistically significant.

3. Results

3.1. Patient Characteristics, and Adherence Rate

Of the 97 recruited patients, 80 (82.5%) met inclusion criteria for analysis after accounting for follow‐up completeness. Demographics and baseline characteristics are summarized in Table 1. The overall cohort was 55.0% female (n = 44), 43.7% male (n = 35), and 1.3% non‐binary (n = 1) with a mean age of 47.9 years (SD = 17.6). The mean baseline SNOT‐22 score was 33.3 (SD = 18.8), and mean VAS was 51.3 (SD = 27.3). A total of 88.7% (n = 71) completed all four follow‐up assessments, 6.3% (n = 5) completed two, and 5.0% (n = 4) completed only one.

TABLE 1.

Sociodemographic, clinical characteristics and adherence of participants.

Characteristic	All cohort	Post‐Op < 3 months	No recent surgery	p a	SNOT‐22 ≥ 20	SNOT‐22 < 20	p a
	(n = 80)	(n = 42)	(n = 38)		(n = 55)	(n = 25)
Age, years, mean ± SD	47.9 ± 17.6	47.7 ± 18.6	48.1 ± 17.2	0.72 a	46.1 ± 17.5	51.7 ± 17.6	0.30 a
Baseline SNOT‐22, mean ± SD	33.3 ± 18.8	31.4 ± 19.1	36.0 ± 18.6	0.41 a	43.2 ± 13.8	11.5 ± 4.0	< 0.001 a
Baseline sinus‐discomfort VAS, mean ± SD	51.3 ± 27.3	46.5 ± 26.4	53.0 ± 27.2	0.48 a	58.8 ± 23.9	34.7 ± 27.5	0.001 a
Adherence over 8 weeks, %–median (IQR)	45 (28–68)	56 (35–76)	42 (21–63)	0.02 a	52 (32–71)	38 (19–58)	0.01 a
Gender
Female, n (%)	44 (55.0)	26 (61.9)	18 (47.4)	0.18 b	32 (58.2)	12 (48.0)	0.38 b
Male, n (%)	35 (43.7)	15 (35.7)	20 (52.6)		22 (40.0)	13 (52.0)
Non‐binary, n (%)	1 (1.3)	1 (2.4)	0		1 (1.8)	0
Ethnicity
Asian, n (%)	9 (11.3)	1 (2.4)	8 (21.1)	0.09 b	8 (14.5)	1 (4.0)	0.42 b
African American, n (%)	5 (6.2)	4 (9.5)	1 (2.6)		3 (5.5)	2 (8.0)
Hispanic/Latino, n (%)	11 (13.8)	8 (19.0)	3 (7.9)		7 (12.7)	4 (16.0)
Pacific Islander, n (%)	1 (1.3)	0	1 (2.6)		0	1 (4.0)
White, n (%)	49 (61.2)	27 (64.3)	22 (57.9)		35 (63.7)	14 (56.0)
Other, n (%)	5 (6.2)	2 (4.8)	3 (7.9)		2 (3.6)	3 (12.0)
Diagnosis
Allergic rhinitis, n (%)	16 (20.0)	0	16 (42.1)	< 0.001 b	13 (23.6)	3 (12.0)	0.04 b
CRS with nasal polyps, n (%)	32 (40.0)	23 (54.8)	9 (23.7)		17 (30.9)	15 (60.0)
CRS without nasal polyps, n (%)	32 (40.0)	19 (45.2)	13 (34.2)		25 (45.5)	7 (28.0)
Comorbidity
Diabetes, n (%)	5 (6.2)	3 (7.1)	2 (5.3)	0.99 b	2 (3.6)	3 (12.0)	0.28 b
Asthma, n (%)	18 (22.5)	11 (26.2)	7 (18.4)	0.43 b	10 (18.2)	8 (32.0)	0.23 b
Surgery status
Never, n (%)	28 (35.0)	0	28 (73.7)	< 0.001 b	22 (44.0)	6 (24.0)	0.04 b
> 1 year, n (%)	9 (11.2)	0	9 (23.7)		10 (18.2)	4 (16.0)
Within 1 year, n (%)	1 (1.3)	0	1 (2.6)		0	1 (4.0)
< 3 months, n (%)	42 (52.5)	42 (100.0)	0		28 (56.0)	14 (56.0)
Surgery desire
No–no need for surgery, n (%)	28 (35.0)	0	28 (73.7)	< 0.001 b	22 (44.0)	6 (24.0)	0.09 b
No–had surgery past 6 months, n (%)	17 (21.3)	0	17 (44.7)		11 (20.0)	6 (24.0)
Yes–no plan yet, n (%)	41 (51.3)	42 (100.0)	0		27 (49.1)	14 (56.0)
Yes–surgery decided, n (%)	4 (5.0)	0	4 (10.5)		4 (7.3)	0
I don't know, n (%)	5 (6.2)	0	5 (13.2)		8 (14.5)	5 (20.0)

Abbreviations: CRS, chronic rhinosinusitis; IQR, interquartile range; mo, months; SD, standard deviation; VAS, visual analog scale; wk., weeks.

^a Mann–Whitney U test for continuous variables (due to skewed adherence and some baseline scores).

^b χ ² test or Fisher's exact test for categorical variables, as appropriate.

Across the full cohort, adherence to budesonide irrigation ranged from 0% to 100%, with a mean of 47.5% (SD = 28.2) over the 8‐week period (Figure 1). Of the total participants analyzed, 42 (52.5%) had undergone endoscopic sinus surgery within the preceding 3 months. This group was selected for a priori analysis because we hypothesized that patients in the early postoperative period may be more motivated to adhere to topical steroid irrigations. There was no difference in age, baseline SNOT‐22 and VAS scores between the recent post‐op and the overall cohort. The median adherence rate over the 8‐week period was 55.6% (IQR 35%–76%) in the recent surgery group, compared with 42% (IQR 21%–63%) in the group without recent surgery (p = 0.0214, Figure 1).

FIGURE 1.

Adherence of budesonide nasal irrigation by cohorts across follow‐ups.

We assessed adherence based on baseline symptom severity by comparing participants with SNOT 22 ≥ 20 to SNOT 22 < 20. A total of 55 participants (68.8%) had baseline SNOT‐22 ≥ 20, indicating moderate‐to‐severe disease burden. The average SNOT‐22 score was 43.2 (SD = 13.8), and mean VAS was 58.8 (SD = 23.9). The increased symptomatic cohort had a median adherence of 51.6% (IQR 0%–65.4%), which was significantly higher than the 38.4% (IQR 0%–58.5%) in the less symptomatic cohort (p = 0.0059, Figure 1).

3.2. Adherence and Symptom Trajectories Over Time

Across the entire cohort, adherence decreased over the 8‐week follow‐up as mean adherence decreased by 23.5% from baseline to week 8 (p < 0.001) with the greatest reduction between baseline and week 4. Mean SNOT‐22 decreased by 18.4 points from baseline to week 8 (p < 0.001) while mean VAS discomfort scores decreased by 24.9 points over the same period (p < 0.001, Figure 2).

FIGURE 2.

Adherence, SNOT‐22, and VAS scores over the 8‐week budesonide irrigation follow‐up.

3.3. Adherence Is Significantly Associated With Symptom Improvement but Not Surgery Desire

Higher adherence to topical steroid nasal irrigations was significantly associated with decreased improvement in symptom scores. Figure 3 illustrates the linear relationship between overall adherence and changes in SNOT‐22 and VAS discomfort scores across participants. Greater adherence was associated with larger reductions in both measures, supporting a dose–response pattern between budesonide irrigation usage and symptomatic improvement. In the overall cohort, each 1% increase in adherence was associated with a 0.19‐point reduction in VAS discomfort (β = −0.192; 95% CI: −0.264, −0.119; p < 0.001) and a 0.10‐point reduction in SNOT‐22 (β = −0.097; 95% CI: −0.136, −0.039; p = 0.024) over time. Adherence was not significantly associated with changes in surgery desire. Concurrent antibiotic use was independently associated with higher SNOT‐22 scores (+1.77 points, p = 0.019).

FIGURE 3.

Scatter plot showing the relationship between adherence to budesonide nasal irrigation and changes in patient‐reported outcomes. Each point represents a participant's change in SNOT‐22 score (blue) or sinus discomfort visual analog scale (VAS) score (red) over the follow‐up period, plotted against their overall adherence percentage. Higher adherence was generally associated with greater reductions in both SNOT‐22 and VAS scores, indicating symptom improvement.

Participants who had undergone recent sinus surgeries had higher adherence rates, and their increased adherence was also significantly associated with decreased VAS and SNOT‐22 scores. For each 1% increase in adherence, patient VAS discomfort scores decreased by 0.18 points (β = −0.165; 95% CI: −0.259, −0.070; p = 0.001), and SNOT‐22 scores decreased by about 0.10 points (β = −0.093; 95% CI: −0.132, −0.035; p = 0.028). Surgery desire was not examined in this group since all participants had already undergone recent surgery. Concurrent antibiotic use was still linked to higher SNOT‐22 (+2.97 points, p = 0.0007).

Participants with more severe baseline symptoms (SNOT‐22 ≥ 20) also had higher adherence compared to the entire cohort, and their increased adherence was also significantly associated with decreased VAS and SNOT‐22 scores. For each 1% increase in adherence, patient VAS discomfort scores decreased by 0.23 points (β = −0.23; 95% CI: −0.40, −0.06; p = 0.043), and SNOT‐22 scores decreased by 0.16 points (β = −0.16; 95% CI: −0.25, −0.07; p < 0.001). Antibiotic use in this group was also associated with significantly higher symptom burden as SNOT‐22 scores were 7.08 points higher when patients were taking antibiotics (β = +7.08, p = 0.005).

Participants with milder baseline symptoms (SNOT‐22 < 20) reported lower adherence on average. Higher adherence was still associated with lower SNOT‐22 scores (β = −0.007, p = 0.021), while the association with VAS was not statistically significant (p = 0.066). No significant associations were found between adherence and changes in surgery‐desire scores in any group.

Comorbidities were evaluated as potential influences of adherence and symptom burden. Patients with diabetes demonstrated significantly lower SNOT‐22 scores across follow‐up visits (β = −0.92, p = 0.024). Asthma was not associated with SNOT‐22 or VAS scores. In random forest models predicting adherence, diabetes, asthma, and concurrent antibiotic use emerged among the strong predictors of higher adherence.

4. Discussion

This prospective, longitudinal study demonstrates that medication adherence is significantly associated with symptom improvement in chronic rhinitis and sinusitis, with the magnitude of clinical benefit varying by baseline disease severity. Across the overall cohort, each 1% increase in adherence was associated with a small but statistically significant improvement in SNOT‐22 and VAS scores. When stratified by baseline symptom burden, the association was substantially stronger in patients with higher SNOT‐22 scores (≥ 20), while attenuated in those with mild symptoms. While the per‐percentage‐point effect size appears numerically small, their cumulative impact is meaningful in the high symptom subgroup. For example, a 50% increase in adherence among patients with greater symptoms corresponds to an expected 8‐point reduction in SNOT‐22—approaching the minimal clinically important difference (MCID) of 8.9 points [14]. These findings suggest that the association between adherence and symptomatic improvement was strongest in patients with moderate‐to‐severe disease where it is most perceptible, underscoring the value of adherence counseling and reinforcement in this cohort.

The relatively small per‐percentage‐point effect size in this study may be attributable to several factors. During follow‐up, some patients reported performing saline irrigations without adding budesonide due to concerns about steroid exposure and potential long‐term side effects. As adherence was quantified objectively via ampule counts, this behavior could affect both adherence and therapeutic effect. While all participants received tutorial on intranasal irrigation, variability in techniques, volume, and timing might affect the amount of steroid reached sinonasal mucosa. Patients with milder baseline symptoms may have experienced ceiling effects in improvement despite high adherence. In patients who had recently undergone surgery, the benefit of adherence may have been attenuated by the healing period or masked by the substantial clinical improvement that surgical intervention alone has provided. Together, these factors might account for a modest but statistically significant association between adherence and outcomes.

Medication adherence appeared most impactful in patients who have undergone recent surgery or those with more severe baseline symptoms. Patients within 3 months of surgery had both higher adherence and stronger associations with symptom improvement. This may reflect heightened motivation in the early post‐operative period and closer in‐person follow‐up contact. Conversely, patients with lower baseline symptom scores (SNOT‐22 < 20) demonstrated lower adherence rates (average < 40%) and did not show a significant association between adherence and VAS score, with only minimal change observed in SNOT‐22.

To achieve the MCID of approximately 9 points, an estimated 50%–60% increase in adherence would be required. Given the overall mean adherence and downward trend over time, such improvement appears attainable through targeted strategies. These findings suggest that while adherence remains clinically relevant, its effect on clinical outcomes may vary depending on individual patient characteristics, particularly baseline disease severity and postoperative status.

To our knowledge, this is the first prospective study to objectively quantify the dose–response relationship between adherence to topical steroid nasal irrigation and patient‐reported sinonasal clinical outcomes using verified ampule‐count rather than self‐reported. While the general importance of medication adherence is well‐established, previous studies mostly relied on subjective adherence measures, and our study employed a novel strategy to minimize recall bias and over‐reporting. These results expand on prior research on the efficacy of topical nasal steroid irrigation [5, 6], especially in postoperative patients [7], by assessing the importance of medication adherence using objective measures rather than self‐report. As self‐reported medication use may be subject to recall bias and overestimation, the use of ampule counts strengthened the validity of our findings. These data suggest that the beneficial effect of topical steroid therapy may be related to adherence and baseline disease severity. Identifying strategies to improve patient adherence, such as simplifying the regimen, offering thorough patient education, and addressing potential barriers to use could potentially lead to better clinical outcomes.

Beyond adherence, several clinical characteristics influenced treatment behavior. Comorbid diabetes and asthma were independently associated with higher adherence, potentially reflecting increased familiarity with chronic medication use and self‐management routines.

We did not observe a significant correlation between adherence and desire for surgery, indicating that surgical decision‐making may be influenced by additional factors beyond symptom control alone. Nonetheless, adherence counseling could still play a supportive role in shared decision‐making for patients weighing surgical options.

Taken together, these findings suggest that real‐world adherence strategies should be implemented alongside prescribing budesonide nasal irrigation. In our cohort, objectively measured adherence averaged only 47.5% and gradually declined over the 8‐week study period, suggesting that adherence should be assessed more thoroughly at each follow‐up visit to identify barriers and close the gap between prescription and actual use. Additionally, the association between adherence and patient‐reported symptom improvement was strongest among patients who had undergone surgery within the past 3 months and those with a baseline SNOT‐22 ≥ 20, suggesting that adherence‐targeted interventions may be particularly effective in these patient subgroups. Lastly, our per‐percentage‐point effect estimate suggests that a 50% increase in adherence corresponds to the minimal clinically important difference [14], providing a practical framework for counseling patients about the expected benefits of improving adherence.

Certain limitations in this study should be acknowledged. As an observational study, this study identifies associations between adherence and patient‐reported outcomes but cannot establish causation. The 8‐week follow‐up period may not capture long‐term adherence patterns or chronic disease variability. The moderate sample size and single‐institution design may limit generalizability, and the 17.5% attrition rate introduces possible bias toward more engaged or symptomatic patients. Additionally, potential confounders such as concurrent medications and environmental exposures causing exacerbations were not fully controlled. Clinical outcomes were assessed using validated patient‐reported instruments VAS and SNOT‐22 but without concurrent endoscopic grading, and future studies should include endoscopic and radiographic findings as another measure of the benefits of higher adherence. This study also combined chronic rhinosinusitis and allergic rhinitis because topical steroid irrigation is a common treatment for both conditions, but they are different diagnoses, and disease‐specific subgroup analyses were limited by sample size. Similarly, this study classified no recent surgery as never received or received sinus surgery over 3 months ago, and a more specific group comparison is an important direction for future studies but was limited in this study by sample size and underpower of statistical analysis. Furthermore, SNOT‐22 and VAS are patient‐reported intermediate endpoints, and downstream effects on hard clinical outcomes cannot be inferred. Future studies with longer‐term follow‐up are needed to determine adherence over extended periods, given the chronic nature of sinusitis and rhinitis.

Due to the complexity of adherence and our intention to maximize survey responses, the questionnaire did not include specific questions about participants' reasons for adherence behavior. However, anecdotal responses included schedule limitations and forgetfulness as common reasons for non‐adherence. Furthermore, many participants reported discontinuing use after experiencing symptomatic improvement as reflected in our longitudinal follow‐up. This highlights the multifaceted nature of adherence, and future studies that feature patient perspectives in medication adherence would be valuable.

5. Conclusion

This study suggests the significant role that adherence to topical steroid sinus rinses plays in improving clinical outcomes among patients with chronic rhinitis and sinusitis. Higher adherence was associated with meaningful reductions in sinus discomfort and SNOT‐22 scores, with amplified associations in patients presenting with more severe baseline symptoms or recent surgery. These findings advocate for enhanced patient education and adherence support strategies that may optimize the benefits of medical management in sinonasal disorders, especially in selected patients where the association was strongest. Addressing concerns about steroid exposure and better teaching of irrigation technique may further strengthen the clinical benefits with improved adherence. Further research is warranted to confirm these results in broader populations and to determine the long‐term sustainability of adherence‐associated improvements.

Funding

This work was supported by the Summer Research Fellowship, UC San Diego School of Medicine.

Disclosure

No artificial intelligence was used in the making of this manuscript.

Consent

All participants provided informed consent before enrollment.

Conflicts of Interest

C.H. received UC San Diego School of Medicine Summer Research Fellowship for the research, authorship, and publication of this article. The other authors declare no conflicts of interest.

Data Availability Statement

The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions.