Evaluating components of dental care utilization among adults with diabetes and matched controls via hurdle models

Dental service use among adults with incident type 2 diabetes, rheumatoid arthritis or inflammatory bowel disease

OBJECTIVES

It is not clear if or how the incidence of systemic conditions like type 2 diabetes mellitus (DM2), rheumatoid arthritis (RA) or inflammatory bowel disease (IBD) affects dental service utilization. Using nationwide Danish register data, the aim of this study was to analyse the use of dental services 7 years before and after being diagnosed with DM2, RA or IBD between 1997 and 2011.

METHODS

Information about incident DM2 was obtained from the National Diabetes Register, and incident RA and IBD were defined based on diagnosis codes of hospital contacts identified through the National Patient Register. Separately, for each of the three conditions, each individual with the incident condition was matched to one control individual based on age, gender, country of origin, municipality of residence, highest completed education, the main source of income and income using coarsened exact matching in the year of incidence. The use of dental services and treatments received within each calendar year from 7 years before to 7 years after getting the condition were analysed with generalized estimating equations.

RESULTS

People with incident DM2 were less likely (by seven percentage points) to be dental service users within a year than people without incident DM2 for a period extending from up to 7 years prior to 7 years after the diagnosis. This difference even slightly increased after the diagnosis. Those with incident IBD exhibited a consistently but modestly higher proportion of dental service use (three percentage points) than those without incident IBD before and after the diagnosis. Differences in the use of services between those with or without incident RA were minor. For all three systemic diseases, detected differences mainly mirrored differences in the provision of supragingival scaling and restorative treatment.

CONCLUSIONS

The findings suggest that the impact of these three systemic conditions on dental service use was minor.

Improving performance of hurdle models using rare-event weighted logistic regression: an application to maternal mortality data

In this paper, performance of hurdle models in rare events data is improved by modifying their binary component. The rare-event weighted logistic regression model is adopted in place of logistic regression to deal with class imbalance due to rare events. Poisson Hurdle Rare Event Weighted Logistic Regression (REWLR) and Negative Binomial Hurdle (NBH) REWLR are developed as two-part models which use the REWLR model to estimate the probability of a positive count and a Poisson or NB zero-truncated count model to estimate non-zero counts. This research aimed to develop and assess the performance of the Poisson and Negative Binomial (NB) Hurdle Rare Event Weighted Logistic Regression (REWLR) models, applied to simulated data with various degrees of zero inflation and to Nairobi county's maternal mortality data. The study data on maternal mortality were pulled from JPHES. The data contain the number of maternal deaths, which is the outcome variable, and other obstetric and demographic factors recorded in MNCH facilities in Nairobi between October 2021 and January 2022. The models were also fit and evaluated based on simulated data with varying degrees of zero inflation. The obtained results are numerically validated and then discussed from both the mathematical and the maternal mortality perspective. Numerical simulations are also presented to give a more complete representation of the model dynamics. Results obtained suggest that NB Hurdle REWLR is the best performing model for zero inflated count data due to rare events.

Impact of diabetes diagnosis on dental care utilization: evidence from Finland

BACKGROUND

Poor oral health is associated with many chronic diseases, including diabetes. As diabetes can worsen oral health and vice versa, care guidelines recommend that patients with diabetes maintain good oral health and have regular dental checkups. We analyzed the impact of receiving an initial type 2 diabetes diagnosis on dental care utilization.

METHODS

We used register data on residents aged over 25 in the city of Oulu, Finland, covering the years 2013-2018. We used the difference-in-differences method and individuals with no diabetes diagnosis as control group. As robustness checks, we used propensity score matching and constructed an alternative control group from patients that received the same diagnosis a few years apart.

RESULTS

Despite the guideline recommendations, we found that receiving a diabetes diagnosis did not increase the probability for dental care visits in a two-year follow-up. The findings remained similar for both high-income and low-income persons.

CONCLUSIONS

The finding is concerning in terms of diabetes management and oral health. Further research is needed on the reasons behind the lack of response to guidelines.

Oral Health and Patterns of Dental Visits Among Diabetic Patients in the Eastern Province of Saudi Arabia

Purpose

Diabetes is a big public health threat in Saudi Arabia. However, there is limited evidence about dental problems, oral hygiene practices, and dental visits among diabetic patients. The study aimed to evaluate self-perceived oral health status and patterns of dental attendance among diabetic patients in the Eastern province of Saudi Arabia.

Methodology

This cross-sectional study included 486 diabetic patients (mean age 50.14±13.59 years) registered with the Saudi Diabetes Society, Saudi Arabia (October–November 2020). The World Health Organization’s oral health questionnaire for adults was administered to collect information about oral health status, oral hygiene practices, and dental attendance, in addition to sociodemographic data. Descriptive and analytical statistics were performed.

Results

Most participants (66.3%) reported having dental pain or discomfort during the last year. Bad breath (60.50%), tooth cavities (55.10%), difficulty in biting hard food (55.10%), tooth sensitivity (53.30%), and bleeding gums (52.90%) were common oral problems among participants. More than half the sample (55.1%) reported visiting the dental office during the last year. However, pain or trouble with teeth, gums or mouth was the most common (40.5%) reason for the last dental visit. Only 7.8% of participants visited the dentist for a routine dental check-up. Multiple logistic regression analysis showed that Saudi nationality (AOR 2.68, P 0.008), family history of diabetes (AOR 1.88, P 0.022), and having pain during the last year (AOR 4.01, P <0.001) were the significant factors associated with the last dental visit due to pain.

Conclusion

This sample of participants demonstrated a high prevalence of dental problems. Few participants performed routine dental visits and most visits were due to pain. Saudis and patients with family history of diabetes and dental pain were more likely to perform pain related dental visits. Multidisciplinary efforts are needed to develop and implement preventive educational and clinical care models for positive oral and general health outcomes.

Dental services use before and after inpatient admission among privately insured adults in the United States

BACKGROUND

Oral health has been connected to worse outcomes among hospitalized patients, but access to oral health care services in the hospital setting is limited. It is unknown how a hospital admission affects subsequent dental services use.

METHODS

The authors conducted a retrospective analysis of insurance claims data from a national private insurer. Patients were included if they were admitted to the hospital and had visited a dentist at least once in the year before or after admission. Total number of dental visits, as well as Code on Dental Procedures and Nomenclature codes associated with these visits in the year before and after a hospital stay, patient demographic characteristics, hospital admission diagnosis, and length of stay were recorded. Differences in dental services use before and after the hospital stay were calculated.

RESULTS

In total, 107,116 patients met inclusion criteria. There were fewer dental visits after admission (mean [standard deviation {SD}] 1.6 [1.7] than before admission (mean [SD] 1.9 [1.8]; P < .0001). Fewer procedures were recorded in the year after discharge (mean [SD] 7.0 [11.4] total Code on Dental Procedures and Nomenclature codes versus 8.5 [12.5] in the year before admission; P < .0001). The number of diagnostic and restorative services delivered was higher after admission, and the number of periodontic, endodontic, oral surgery, and prosthodontic services decreased (overall Pearson χ², P < .0001).

CONCLUSIONS

Patients are less likely to visit a dentist after a hospital stay, although impact on oral health is unknown.

PRACTICAL IMPLICATIONS

Hospitalization may contribute to already existing oral health disparities. Hospital teams and dentists should work together to enhance access to oral health care after hospital admission.

Diabetes and Oral Health: Summary of Current Scientific Evidence for Why Transdisciplinary Collaboration Is Needed

This Perspective provides a brief summary of the scientific evidence for the often two-way links between hyperglycemia, including manifest diabetes mellitus (DM), and oral health. It delivers in a nutshell examples of current scientific evidence for the following oral manifestations of hyperglycemia, along with any available evidence for effect in the opposite direction: periodontal diseases, caries/periapical periodontitis, tooth loss, peri-implantitis, dry mouth (xerostomia/hyposalivation), dysbiosis in the oral microbiome, candidiasis, taste disturbances, burning mouth syndrome, cancer, traumatic ulcers, infections of oral wounds, delayed wound healing, melanin pigmentation, fissured tongue, benign migratory glossitis (geographic tongue), temporomandibular disorders, and osteonecrosis of the jaw. Evidence for effects on quality of life will also be reported. This condensed overview delivers the rationale and sets the stage for the urgent need for delivery of oral and general health care in patient-centered transdisciplinary collaboration for early detection and management of both hyperglycemia and oral diseases to improve quality of life.

Incremental Dental Expenditures Associated With Diabetes Among Noninstitutionalized U.S. Adults Aged ≥18 Years Old in 2016-2017

OBJECTIVE

Diabetes is associated with poor oral health, but incremental expenditures for dental care associated with diabetes in the U.S. are unknown. We aimed to quantify these incremental expenditures per person and for the nation.

RESEARCH DESIGN AND METHODS

We analyzed data from 46,633 noninstitutionalized adults aged ≥18 years old who participated in the 2016-2017 Medical Expenditure Panel Survey. We used two-part models to estimate dental expenditures per person in total, by payment source, and by dental service type, controlling for sociodemographic characteristics, health status, and geographic variables. Incremental expenditure was the difference in predicted expenditure for dental care between adults with and without diabetes. The total expenditure for the U.S. was the expenditure per person multiplied by the estimated number of people with diabetes. Expenditures were adjusted to 2017 USD.

RESULTS

The mean adjusted annual diabetes-associated incremental dental expenditure was $77 per person and $1.9 billion for the nation. Of this incremental expenditure, 51% ($40) and 39% ($30) were paid out of pocket and by private insurance, 69% ($53) of the incremental expenditure was for restorative/prosthetic/surgical services, and adults with diabetes had lower expenditure for preventive services than those without (incremental, -$7). Incremental expenditures were higher in older adults, non-Hispanic Whites, and people with higher levels of income and education.

CONCLUSIONS

Diabetes is associated with higher dental expenditures. These results fill a gap in the estimates of total medical expenditures associated with diabetes in the U.S. and highlight the importance of preventive dental care among people with diabetes.

Implementation of an Oral Care Protocol for Primary Diabetes Care: A Pilot Cluster-Randomized Controlled Trial

PURPOSE

Although diabetes care guidelines recommend paying attention to oral health, the effect on daily practice has been limited, and patients with diabetes have yet to benefit. We investigated whether implementation of an oral care protocol for general practitioners (GPs [family physicians]) can improve patient-centered outcomes for patients with type 2 diabetes.

METHODS

Twenty-four GP offices were randomly assigned to the experimental or control group (12 offices each). In the experimental group, GPs and nurse practitioners implemented an oral care protocol. No extra attention was given to oral health in the control group. The primary outcome parameter was oral health-related quality of life (QoL) assessed with the 14-item Oral Health Impact Profile at baseline and 1 year later. Other outcomes were self-reported oral health complaints and general health-related QoL (36-item Short Form Health Survey).

RESULTS

Of 764 patients with type 2 diabetes, 543 (71.1%) completed the 1-year follow-up. More patients reported improved oral health-related QoL in the experimental group (35.2%) compared to the control group (25.9%) (P = .046; P_adj = .049). In a secondary post hoc analysis including GP offices with ≥60% patient follow-up (n = 18), improvement was 38.3% and 24.9%, respectively (P and P_adj = .011). Improvement of self-reported oral health complaints did not differ between groups. The intervention had no effect on general health-related QoL, with the exception of the concept scale score for changes in health over time (P_adj = .033).

CONCLUSIONS

Implementation of an oral care protocol in primary diabetes care improved oral health-related QoL in patients with type 2 diabetes.

Accuracy of a 7-Item Patient-Reported Stand-Alone Tool for Periodontitis Screening

Periodontitis is interrelated with various other chronic diseases. Recent evidence suggests that treatment of periodontitis improves glycemic control in diabetes patients and reduces the costs of diabetes treatment. So far, however, screening for periodontitis in non-dental settings has been complicated by a lack of easily applicable and reliable screening tools which can be applied by non-dental professionals. The purpose of this study was to assess the diagnostic accuracy of a short seven-item tool developed by the German Society for Periodontology (DG PARO) to screen for periodontitis by means of patient-reported information. A total of 88 adult patients filled in the patient-reported Periodontitis Risk Score (pPRS; range: 0 points = lowest periodontitis risk; 20 points = very high periodontitis risk) questionnaire before dental check-up at Heidelberg University Hospital. Subsequent clinical assessments according to Periodontal Screening and Recording (PSR®) were compared with pPRS scores. The diagnostic accuracy of pPRS at different cutoff values was assessed according to sensitivity, specificity, positive, and negative predictive values, as well as Receiver-Operator-Characteristic curves, Area Under the Curve (AUC), and logistic regression analysis. According to combined specificity and sensitivity (AUC = 0.86; 95%-CI: 0.76-0.95), the diagnostic accuracy of the pPRS for detecting periodontal inflammation (PSR® ≥ 3) was highest for a pPRS cutoff distinguishing between pPRS scores < 7 vs. ≥ 7. Patients with pPRS scores ≥ 7 had a 36.09 (95%-CI: 9.82-132.61) times higher chance of having a PSR® ≥ 3 than patients with scores < 7. In conclusion, the pPRS may be considered an appropriately accurate stand-alone tool for the screening for periodontitis.

Prevention and management of periodontal diseases and dental caries in the older adults

As a result of aging populations, in the future, dental practitioners will be caring for more older adults than ever before. These older adults, especially in developed countries, will demand a greater number of dental services, driven by increased tooth retention and an expectation of excellent oral healthcare throughout the life course. Further, the global rise in the prevalence and incidence of chronic diseases will increase the risk and/or severity of oral diseases and add a layer of complexity to the management of oral diseases in older adults. More older adults will be at a higher risk of periodontal disease and root caries as a result of reduced tooth loss and edentulism. This article reviews information on periodontitis and root caries, oral diseases which reflect the cumulative risk of the individual, and which are best addressed through prevention. Oral healthcare providers must embrace the concept of lifelong emphasis on prevention, as well as participation as active members of a healthcare team which provides healthcare for older adults in various settings (eg, hospital/clinic-based care, community-based settings, and long-term care facilities). National guidelines that address oral health are being considered by some countries, and if these are implemented they will increase the accessibility to oral health for older adults. In parallel to this, revisions of existing older adult insurance schemes (eg, the inclusion of routine oral healthcare in the US Medicare program) would promote the maintenance of a functional dentition that is pain-free and conducive to general health. The opportunity exists to implement a holistic approach to oral health that will align oral health with general health and emphasize that true health can only be achieved with the inclusion of oral health.

Methodological approaches for investigating links between dental and chronic diseases with claims data: A scoping study

OBJECTIVES

The purpose of this study was to provide an overview of methodological approaches to assess the relationship between dental diseases and other noncommunicable diseases on the basis of claims data.

METHODS

Based on the methodological framework of Arksey and O'Malley, a scoping study was conducted. By searching electronic databases (PubMed, Web of Science, and LILACS), appropriate articles were identified. After extracting relevant information and entering it into a data-charting form, the study characteristics and the methodological approaches were summarized descriptively.

RESULTS

Fifty-one articles were identified for inclusion in the analysis. Most of the selected studies (78 percent) originated from Taiwan and employed a cohort design. The majority of studies considered dental diseases, particularly periodontal disease (PD) measures, but no common standard was identified for the definition of PD. Unmeasured confounding, misclassification, and surveillance bias were reported to be the main limitations of the claims data analyses.

CONCLUSIONS

Claims data provide a very useful information source to further delineate the relationship between PDs and other noncommunicable diseases. If diagnostic codes are available, they seem to be the most suitable tool to assess PD in claims-based studies. In databases that do not contain dental diagnostic codes, e.g., databases in Germany and the United States, the identification of PD is a particular challenge. The inclusion of dental diagnostic codes in all claims databases is strongly recommended. Due to the public health relevance of PD, there is a need for more comprehensive documentation of dental parameters within claims data.

Self-reported oral health and quality of life in patients with type 2 diabetes mellitus in primary care: a multi-center cross-sectional study

Background: Guidelines for primary diabetes care recommend to pay attention to oral health in patients with diabetes mellitus type 2 (T2DM). However, research about dental care utilization and the extent of problems regarding oral health in these patients is limited. Purpose: To assess self-reported oral health, general health-related quality of life (QoL) and oral health-related QoL in patients with T2DM who regularly attend a family physician office. Methods: Family physician offices were recruited in the area of Amsterdam, the Netherlands, as part of a cluster-randomized controlled trial. At these offices, patients with T2DM were included by family physicians and/or nurse practitioners. Patient data on general characteristics, self-reported oral health (including periodontitis), general health-related QoL (SF-36) and oral health-related QoL (OHIP-NL14) were collected. Results: Twenty-four family physician offices participated, who enrolled 764 patients with T2DM (mean age: 65.9±10.7 years, 56% male, 16% smoker). Almost 11% of the patients were metabolically poorly controlled (HbA1c >63 mmol/mol), 39% were obese (body mass index≥30 kg/m2), 37% had hypertension (systolic blood pressure ≥140 mmHg) and 44% had dyslipidemia (LDL-cholesterol >2.5 mmol/L). About a quarter (24%) reported not to visit a dentist regularly and 30% did not have dental insurance coverage. Furthermore, 16% of the patients were edentulous and having full dental prostheses, while 29% had a partial dental prosthesis. Pain in the mouth, dry mouth and bad breath were reported by 15%, 37% and 12% of the patients, respectively. Almost 70% suffered from periodontitis. Oral health-related QoL was impaired in 19% of the patients, and those subjects also had worse general health-related QoL. Conclusion: Almost a quarter of patients with T2DM at Dutch family physician offices does not visit the dentist regularly. The estimated prevalence of periodontitis is particularly high, but other oral health complaints and impaired oral health-related QoL are also relatively common.

Knowledge and practices of diabetes care providers in oral health care and their potential role in oral health promotion: A scoping review

AIM

Oral health complications are common in people with diabetes yet very little is reported about the oral health care provided in diabetes care setting. This study reviewed global evidence on the oral health care knowledge and practices of diabetes care providers and the role of non-dental health professionals in oral health promotion.

METHODS

A systematic search of five databases was undertaken with key search terms using a scoping review framework. Relevant studies published till October 2016 in the English language were included (n=30) and no restrictions were placed on the study design, quality or setting.

RESULTS

Most diabetes care providers are not addressing oral health care with the main barriers being time constraints and limited oral health knowledge. Diabetes educators (DEs) could engage in oral health promotion with few studies showing this model of care can translate into improved patient outcomes. However, no appropriate oral health training programs and assessment tools exist for DEs. With proper training, non-dental professionals like nurses have successfully incorporated oral healthcare in other settings.

CONCLUSIONS

DEs are well placed to promote oral health in diabetes care setting. Further research is needed to identify barriers and oral health resources to support DEs in this role.

Preventive dental care in older adults with diabetes

BACKGROUND

The association between poor oral health and diabetes is well documented. Preventive oral health care is, therefore, strongly indicated for people with diabetes. The authors conducted a study to determine if there was a difference in preventive dental care use among older adults with diabetes in 2002 and in 2011 and to compare preventive dental care use by older adults with and without diabetes in 2002 and in 2011.

METHODS

The authors used a data sample of participants from the Medicare Current Beneficiary Survey that included older (65 years and older) fee-for-service Medicare beneficiaries. The key outcome was self-reported preventive dental care. In 2002, there were 8,725 participants; in 2011, there were 7,425 participants. The authors conducted χ(2) and logistic regression analyses.

RESULTS

In 2002, 28.8% of participants with diabetes had preventive dental care. In 2011, this percentage increased to 36.0%. Similar results were seen among participants without diabetes (42.9% in 2002 and 45.5% in 2011). The increase in preventive dental care was statistically significant for participants with and without diabetes. The participants with diabetes, as compared with participants without diabetes, remained statistically less likely to have had preventive dental care in adjusted logistic regression analysis with and without considering the interaction between observation year and diabetes (adjusted odds ratios, 0.73 and 0.86, respectively).

CONCLUSIONS

Although the percentage increase in participants with diabetes receiving preventive dental care is welcomed, older adults with diabetes continue to have substantial preventive dental care needs.

PRACTICAL IMPLICATIONS

Additional efforts are needed to encourage people with diabetes to obtain preventive dental care.

Predictors of Adherence to Multiple Clinical Preventive Recommendations among Adults with Diabetes in Spain

OBJECTIVE

This study aims to describe adherence to seven clinical preventive services among Spanish adults with diabetes, to compare adherence with people without diabetes and to identify predictor of adherence to multiple practices among adults with diabetes.

DESIGN

Cross-sectional study based on data obtained from the European Health Survey for Spain 2009 and the Spanish National Health Survey 2011. We analyzed those aged 40-69 years (n= 20,948). Diabetes status was self-reported. The study variables included adherence to blood pressure (BP) checkup, cholesterol measurement, influenza vaccination, dental examination, fecal occult blood test (FOBT), mammography and cytology. Independent variables included socio-demographic characteristics, variables related to health status and lifestyle factors.

RESULTS

The study sample included 1,647 subjects with diabetes and 19,301 without. Over 90% had measured their BP and cholesterol in the last year, 44.4% received influenza immunization, 36.4% had a dental checkup within the year and only 8.1% underwent a FOBT. Among diabetic women 75.4% had received a mammography and 52.4% a cytology in the recommended periods. The adherence to BP and cholesterol measurements and influenza vaccination was significantly higher among those suffering diabetes and cytology and dental checkup were lower. Only 63.4% of people with diabetes had fulfilled half or more of the recommended practices. Female sex, higher educational level, being married or cohabiting, higher number of chronic conditions and number of physician visits increased the adherence to multiple preventive practices. For each unhealthy lifestyle reported the probability of having a higher adherence level decreased.

CONCLUSIONS

Acceptable adherence is found for BP and cholesterol checkups and mammography. Unacceptably low rates were found for influenza vaccine, dental care, cytology and FOBT. Moreover, preventive services are provided neither equitably nor efficiently so future research needs to identify individual and organizational factors that allow interventions to reach these subjects with diabetes.

Propensity score weighting: an application to an Early Head Start dental study

OBJECTIVES

Nonrandomized group assignment in intervention studies can lead to imbalances in preintervention covariates and biased effect estimates. We use propensity score estimation to account for such imbalances in an Early Head Start (EHS) dataset with rich pretreatment information. We compare propensity score results using standard logistic regression models (LRMs) versus generalized boosted models (GBMs).

METHODS

We estimated propensity scores using 47 socio-demographic characteristics and EHS enrollment criteria obtained by parent interviews from a state-wide sample of 637 EHS and 930 Medicaid-matched control children. LRMs and GBMs were used to estimate propensity scores related to EHS enrollment. Performance of both approaches was evaluated via a) measures of balance of pretreatment covariate distributions between treated and control subjects, and b) stability of propensity score weights measured by the effective sample size.

RESULTS

Distributions of all variables were balanced for EHS and non-EHS groups using propensity score weights calculated with LRM and GBM. Compared with LRM, GBM resulted in better balance between treated and propensity score-weighted control distributions. The effective sample size of the controls decreased from 930 subjects to 507 with GBM and to 335 with LRM.

CONCLUSION

Although propensity scores derived from GBM and LRM both effectively balanced observed preintervention covariates, GBM resulted in better covariate balance compared with LRM. GBM also resulted in a larger effective sample size of the control group compared with LRM. Propensity score weighting using GBM is an effective statistical method to reduce confounding due to imbalanced distributions of measured preintervention covariates in this EHS intervention study.

Reusing electronic patient data for dental clinical research: a review of current status

OBJECTIVES

The reuse of electronic patient data collected during clinical care has received increased attention as a way to increase our evidence base. The purpose of this paper was to review studies reusing electronic patient data for dental research.

DATA SOURCES

1527 citations obtained by searching MEDLINE and Embase databases, hand-searching seven dental and informatics journals, and snowball sampling.

STUDY SELECTION

We included studies reusing electronic patient data for research on dental and craniofacial topics, alone or in combination with medical conditions, medications and outcomes. Studies using administrative or research databases and systematic reviews were excluded. Three reviewers extracted data independently and performed analysis jointly

RESULTS

The 60 studies reviewed covered epidemiological (32 studies), outcomes (16), health services research (10) and other (2) topics; were primarily retrospective (58 studies); varied significantly in sample size (9-153,619 patients) and follow-up period (1-12 years); often drew on other data sources in addition to electronic ones (25); but rarely tapped electronic dental record (EDR) data in private practices (3). Type of research was not associated with data sources used, but research topics/questions were. The most commonly reported advantages of reusing electronic data were being able to study large samples and saving time, while data quality and the inability to capture study-specific data were identified as major limitations.

CONCLUSIONS

Dental research reusing electronic patient data is nascent but accelerating. Future EDR design should focus on enhancing data quality, begin to integrate research data collection and implement interoperability with electronic medical records to facilitate oral-systemic investigations.

CLINICAL SIGNIFICANCE

Measuring and improving the quality of dental care requires that we begin to reuse electronic patient data collected in practice for clinical research. Practice data can potentially serve as a useful complement to data collected in traditional research studies.