Gingival Bleeding and Von Willebrand Disease Typ 2 and 3
Condition: Gingival Bleeding; Von Willebrand Diseases
MeSH terms: Gingival Hemorrhage; Von Willebrand Diseases; Hemorrhage
Study type: Observational

Summary: 
      Von Willebrand disease (VWD) is the most common inherent bleeding disorder resulting in
      prolonged bleeding time. Gingival bleeding is a frequently reported symptom of VWD. However,
      gingival bleeding is also known as a leading symptom of plaque-induced gingivitis and
      untreated periodontal disease. Gingival bleeding in VWD patients may be triggered by gingival
      inflammation and not a genuine symptom. Thus, this study evaluates whether type 2 and 3 VWD
      determines an increased susceptibility to gingival bleeding in response to the oral biofilm.
    

Detailed description: 
      Patients

      All patients with type 2 and 3 VWD consecutively consulting the Haemophilia Centre, Medical
      Clinic III/Institute for Transfusion medicine, Hospital of the Johann Wolfgang
      Goethe-University Frankfurt/Main are asked to participate in this study as cases. They are
      asked for bleeding and subjective symptoms indicating periodontal disease.

      The study complies with the rules of the Declaration of Helsinki and was approved by the
      Institutional Review Board for Human Studies of the Medical Faculty of the Goethe-University
      Frankfurt/Main (Application# 143/15). All participating individuals are informed on risks and
      benefits as well as the procedures of the study and give written informed consent.

      Controls

      For each case (VWD) a respective hematologically healthy control is recruited from the
      gingivitis and periodontitis patients of the Department of Periodontology, Centre for
      Dentistry and Oral Medicine (Carolinum), Johann Wolfgang Goethe-University Frankfurt/Main.
      Each control is matched to one of the respective cases for sex, age (±5 years), self-reported
      smoking status (current smoker/non-smoker), number of remaining teeth (±2 teeth), and
      periodontal diagnosis (gingivitis, chronic or aggressive periodontitis).

      All participants are asked about current and past cigarette smoking habits. Patients who
      report smoking or have quit smoking for less than five years are classified as smokers.
      Additionally the amount of carbon monoxide (CO) in exhaled air is measured using a device
      (Bedfont Smokerlyzer; Bedfont Scientific Ltd, Rochester, Great Britain).

      Hematologic examinations

      20 ml of blood are sampled from an arm vein. The following data are assessed at the
      Haemophilia Centre for clinical routine during VWD patient care and due to study design in
      the controls:

        -  von Willebrand parameters (VWF antigen [VWF:Ag], Ristocetin cofactor [VWF:RCo],
           coagulation factor VIII [FVIII:C])

        -  Current medication if any VWF:Ag and VWF:RCo were measured turbidimetrically using a
           device (BCS, Siemens, Marburg, Germany). FVIII:C was assessed with specific agents on a
           coagulation analyser (ACL-300®, Instrumentation Laboratory, Kirchheim, Germany).

      Periodontal examinations

      The following clinical parameters are assessed at 6 sites per tooth (mesiobuccal, buccal,
      distobuccal, mesiolingual, lingual, distolingual):

        -  modified Gingival Bleeding Index (GBI)

        -  modified Plaque Control Record (PCR)

        -  PPD and recession to the nearest 0.2 mm using an electronic probe (Florida Probe,
           Version 3.2, Gainesville, USA). Recession is assessed from the cemento-enamel junction
           (CEJ) to the gingival margin. At sites where the CEJ was destroyed by restorations the
           restoration margin (RM) is used as reference. At sites where the CEJ or RM is located
           apically from the gingival margin the value for recession is negative

        -  Bleeding on probing (BOP) recorded as positive when bleeding occurs within 30 seconds
           from probing. For each patient a BOP index is calculated providing the amount of sites
           with positive BOP in % per patient.

      Attachment loss (PAL-V) is calculated as sum of PPD and recession.

      All individuals are classified into the following diagnoses:

        -  plaque-induced gingivitis (PPD < 3.6 mm; PAL-V ≤ 2 mm),

        -  generalized mild, localized moderate chronic periodontitis (PPD ≥ 3.6 mm; vertical
           probing attachment level [PAL-V] 3 to 4 mm ≤ 30% of sites; 1 to 2 mm > 30% of sites),

        -  generalized mild, localized severe chronic periodontitis (PPD ≥ 3.6 mm; PAL-V ≥ 5 mm ≤
           30% of sites; 1 to 2 mm > 30% of sites)

        -  generalised moderate chronic periodontitis (PPD ≥ 3.6 mm; PAL-V 3 to 4 mm > 30%)

        -  generalised moderate localised severe chronic periodontitis (PPD ≥ 3.6 mm; PAL-V 3 to 4
           mm > 30%; ≥ 5 mm ≤ 30%)

      In all individuals hematological and periodontal examinations are obtained within 24 hours.
      After dental and periodontal examination all patients receive oral hygiene instructions and
      professional tooth cleaning. In cases of untreated periodontal disease periodontal treatment
      is offered. VWD are asked to report any bleeding complications after periodontal probing and
      professional tooth cleaning.

      Statistical analysis

      The individual patient is used as statistical unit. All analyses are performed on patient
      level. GBI is defined as the main outcome variable and BOP as secondary outcome variable. All
      other parameters are control variables. Up to now there are no studies comparing GBI or BOP
      between VWD type 2 and 3 cases and hematologically healthy controls and there are no standard
      deviations of mean GBI and BOP for cases and controls. To detect a clinically relevant
      inter-group difference of 4% GBI or BOP with a type 1 error alpha < 0.05 and a test power of
      80% with a standard deviation of group means of 5.5% a sample size of at least 31 individuals
      is required per group. Thus, it was decided to recruit 31 VWD cases and respectively matched
      31 controls.

      For all individuals, cigarette pack years are calculated. Group frequencies (VWD, control)
      are expressed for sex, current smoking. Group means and standard deviations are calculated
      for GBI, BOP, age, number of remaining teeth, pack years, CO, PCR, VWF:Ag, VWF:RCO, FVIII:C.
      Further, for each individual the following variables are calculated to describe the
      periodontal status:

        -  Mean±standard deviation of PPD and PAL-V

        -  Percentage of PPD < 4 mm, 4 to 6.8 mm, ≥ 7 mm

        -  Sum of all PPD, i.e. the sum of the PPD measured at all sites within a patient

        -  Sum of all PPD with BOP, ), i.e. the sum of the PPD measured at all sites exhibiting BOP
           within a patient

        -  Periodontal inflamed surface area (PISA). For each patient PPD were entered into an
           Excel sheet that can be downloaded freely (http://www.parsprototo.info/pisa.html).

      From these group means and standard deviations are calculated. Comparisons between groups for
      dichotomous parameters are made by χ² or Fisher's exact test and for all other parameters by
      Mann-Whitney-U test. A post-hoc analysis is performed to estimate the test power that would
      be required to find a clinically relevant inter-group difference (δ) of 5% for GBI and BOP
      index with a type 1 error (α) of 0.05 for the actual sample size.

      Using stepwise linear backward multiple regression analysis, factors shall be identified that
      influence GBI and BOP. The following independent variables are entered into the model for
      GBI: group (VWD/control), sex, age, number of remaining teeth, PCR, CO, pack years, PISA. The
      following independent variables are entered into the model for BOP: group (VWD/control), sex,
      age, number of remaining teeth, PCR, CO, pack years, PISA. Due to the fact that mean PPD is
      mathematically coupled to sum of PPD, sum of PPD with BOP, and PISA these 4 variables are not
      entered into the regression model at the same time. PISA provides the best representation of
      the subgingival inflamed area. Thus, PISA is chosen for the final model. The following
      parameters are described by dummy variables: group (control = 0, VWD = 1), sex (male = 0,
      female = 1), smoking status (never and former smoker = 0, current smoker = 1). All factors
      with p < 0.1 are kept in the models. For statistical analysis a PC program is used (SystatTM
      for Windows Version 12, Systat Inc., Evanston, USA).
    

Observational model: Case-Control
Time perspective: Cross-Sectional
Sampling method: Non-Probability Sample
Study population: 
        Cases with type 2 and 3 VWD consecutively consulting the Haemophilia Centre, Medical Clinic
        III/Institute for Transfusion medicine, Hospital of the Johann Wolfgang Goethe-University
        Frankfurt/Main are asked to participate in this study as cases. For each case (VWD) a
        respective haematologically healthy matched control is recruited from the gingivitis and
        periodontitis patients of the Department of Periodontology, Centre for Dentistry and Oral
        Medicine (Carolinum), Johann Wolfgang Goethe-University Frankfurt/Main.
      
Keywords: periodontal disease; plaque-induced gingivitis; bleeding on probing; von willebrand disease; gingival bleeding