Evaluation of diagnostic and prognostic value of clinical characteristics of Migraine and Tension type headache included in the diagnostic criteria for children and adolescents in International Classification of Headache Disorders – second edition

Authors


  • Disclosures
    We declare that there are no possible conflicts of interest, no sources of financial support, no corporate involvement for each author.

Iliyana Hristova Pacheva,
10, Rozhen Str., Plovdiv, 4000, Bulgaria
Tel.: +359 32 250 893
Fax: +359 32 602547
Email: inapatcheva@hotmail.com

Summary

Data about the sensitivity and the specificity of the items included in the diagnostic criteria for migraine and tension type headache (TTH) in children is limited and sometimes controversial.

Aim:  To evaluate the diagnostic value of characteristics of migraine and TTH included in the diagnostic criteria of ICHD–II and according to results to suggest additional criteria for diagnostic differentiation of primary paediatric headache.

Patients and methods:  The investigation consisted of an epidemiological school-based study (1029 pupils completed the study and 412 had chronic or recurrent headache) and a clinical study conducted in Paediatric Neurology Ward and outpatient clinic (203 patients with chronic or recurrent headache). Inclusion criterion was at least two episodes of headache during the last year. Exclusion criteria were: headache occurring only during acute infections; withdrawal of informed consent. ICHD – II was used to classify headache. The diagnostic value of characteristics of migraine and TTH was measured using sensitivity, specificity, odds ratio and area under receiver operating characteristic curve (AUC).

Results:  Regarding the AUC, the best diagnostic items for migraine are: moderate or severe intensity or only severe intensity, pain aggravation by physical activity, pulsating quality, respectively, for TTH – no photophobia, no nausea, no aggravation by physical activity, mild or moderate intensity and non-pulsating quality. The most significant symptom for increasing the migraine risk was pulsating pain and the most significant items for TTH risk were no photophobia, bilateral location and no nausea. Family history of migraine also increased migraine risk and could be either included in the diagnostic criteria for migraine or recommended as additional item in differentiating migraine and TTH with overlapping diagnostic criteria. According to AUC, we could recommend changing the content of the item of intensity for migraine as only severe intensity.

What’s known

Tension type headache (TTH) and migraine are the most frequent types of headache in children and adolescents. Data about the sensitivity and the specificity of the items included in the diagnostic criteria for migraine and TTH is limited and sometimes controversial.

What’s new

The most significant symptom for increasing the migraine risk was pulsating pain, followed by pain aggravation by physical activity, moderate-to-severe intensity and nausea. The most significant items for increased TTH risk were no photophobia, bilateral location and no nausea. Family history of migraine also increased migraine risk and could be either included in the diagnostic criteria for migraine or recommended as additional item in differentiating migraine and TTH with overlapping diagnostic criteria. According to AUC, we could recommend changing the content of the item of intensity for migraine as only severe intensity.

Introduction

The incidence of primary headache in children and adolescents is increasing in the recent years and chronic or recurrent headache is becoming a significant social problem (1–10). Tension type headache (TTH) and migraine are the most frequent types of headache not only in adults, but also in children and adolescents (3,5,11–17). The precise diagnosis of the type of headache is very important for adequate treatment, but is hindered by the overlap in the symptoms of these two entities. Cases of migraine have been reported presenting with tightening headache or with no aggravation by physical activity and no associated symptoms, and correspondingly – TTH cases in children, especially of younger age, have been reported with pulsating or unilateral headache or with aggravation by physical activity (6,18–20). These overlapping characteristics of migraine without aura and episodic TTH led to the conclusion that distinction between these two entities may be difficult or even impossible (21,22).

Migraine in children has specific characteristics different from adult migraine. Some revisions in the diagnostic criteria for migraine in children were accepted in the International Classification of Headache Disorders – second edition (ICHD – II), which increased the difference between the criteria for children and for adults. The revisions include shorter duration of migraine attack in children – 1 h, instead of 4 h for adults; either unilateral or bifrontal or bitemporal location, instead of only unilateral location for adults; photo- or phonophobia, instead of photo- and phonophobia for adults. There were no revisions of diagnostic criteria for TTH in the ICHD – II, despite some suggestions, i.e. three, but not two out of four items to be required for criterion C, as well as to have no associated symptoms instead of not more than one of the two – photophobia and phonophobia, for criterion D. The reason for not accepting these suggestions was that the recommended new criteria had high specificity (Sp), but low sensitivity (Se) (23).

The diagnostic criteria for primary headache are under constant discussion (18,19,21,24–31). Rasmussen et al. recommended the item intensity to be a separate criterion and associated symptoms to be evaluated according to their severity (21). Messinger et al. suggested all items of the diagnostic criteria to be separate criteria (32).

Data about the Se and the Sp of the items that characterise headache included in the diagnostic criteria of the ICHD – II for migraine or TTH is limited and sometimes controversial (6,18,22,25,30,33–35). Further investigations will be required to optimise the criteria in the next classification so that they to suit clinical practice better.

Aim

The aim of this study is to evaluate the diagnostic value of the symptoms of migraine and TTH included in the diagnostic criteria of ICHD – II and according to the results to suggest additional criteria for diagnostic differentiation of primary headache.

Patients and methods

The present investigation consisted of two subsets – an epidemiological study and a clinical study.

Epidemiological study

Epidemiological study was a school – based study among 7- to 17-year-old students in the schools of Plovdiv region of Bulgaria. Plovdiv is the second city of Bulgaria. Random sampling was made among the public schools from urban and rural districts of Plovdiv. A total of 1063 pupils aged 7–17 years were randomly selected from three different schools.

Inclusion criterion was at least two episodes of headache during the last year. Exclusion criteria were: (i) Headache occurring only during acute infections; (ii) Withdrawal of informed consent.

The study was approved by the Plovdiv Medical University Ethics Committee and by the school authorities. Confidentiality was guaranteed to all pupils and their parents.

A total of 1029 pupils (96.8% of the selected) completed the study.

The epidemiological study was conducted in four steps.

I step: Questionnaire

All selected students received a specially designed questionnaire from their teachers or the school nurse/physician. It contained 21 questions inquiring all characteristic features of headache syndromes according to the ICHD-II diagnostic criteria. It was also used to collect information about additional factors, such as headache frequency, family history, possible triggering factors, associated conditions or diseases, etc. Students above the age of 10 filled in the questionnaire on their own. The others did it at home with their parents and then returned it to their teacher.

II step: Clinical interview, physical and neurological examination

It was performed by a team of three headache experts lead by a paediatric neurologist in the month after step I. The interview followed the structure of the questionnaire and gave additional explanation of the questions, which had been misunderstood. In case of discrepancy between the answers in the questionnaire and during the interview, the latter was accepted as correct. Physical examination focused on height, weight, head circumference, rash, pigmentations and depigmentations; nasal obstruction, palpable pain over nasal sinuses, auscultation for murmurs over the neck and temporal bone, heart auscultation, blood pressure. Neurological examination included evaluation of muscle tone and strength, reflexes, sensation, coordination and gait.

III step: Additional consultations and investigations

Ophthalmologic, otorhinolaringologic, EEG, Doppler sonography, imaging (CT or MRI) and laboratory investigations, such as CBC, electrolytes, hormones, were performed in cases where secondary headache was suspected.

IV step: Classification

Each case with headache was classified according to the diagnostic criteria of ICHD – II – 2004 year.

Clinical study

It included 203 newly diagnosed patients with chronic or recurrent headache from the 2509 children who were admitted to the Paediatric Neurology Ward at Plovdiv Medical University Hospital, or treated as outpatients in the 5-year period between 2002 and 2006. The clinical study used the same inclusion and exclusion criteria as the epidemiological one. It started from step II and progressed to step IV of the previously described study design.

After classification of the headache by type, patients from the epidemiological and clinical studies with identical headache types were analysed.

The study design is presented on Figure 1.

Figure 1.

 Study design

The definitions of headache characteristics and the differentiation of clinical characteristics are listed in Appendix 1.

The diagnostic value of the clinical characteristics included in the diagnostic criteria for paediatric migraine, respectively, for TTH in ICHD – II and two other factors – vertigo and family history of migraine was investigated using statistical parameters.

The evaluated characteristics for migraine were: unilateral location, migrainous (combination of unilateral, bifrontal and bitemporal) location, severe intensity, moderate or severe intensity, pulsating quality, pain aggravation by daily physical activity, nausea, vomiting, photophobia, phonophobia, photo- or phonophobia, vertigo/lightheadedness and family history of migraine.

The evaluated characteristics for TTH were: bilateral location, mild intensity, mild or moderate intensity, tightening-pressing quality, non-pulsating quality, no pain aggravation by daily physical activity, no nausea, no vomiting, no photophobia, no phonophobia, no vertigo/lightheadedness and no family history of migraine.

Statistical methods

Parametric and non-parametric, correlative, linear and nonlinear regressive analyses were applied using SPSS 11 software.

Different tests of statistical significance were applied as appropriate: t-test, Fisher exact test, chi-square, Kolmogorov–Smirnov test and Kruskal–Wallis H-test (p < 0.05 was considered statistically significant).

The diagnostic value of the clinical characteristics was measured using Se, Sp, odds ratio (OR) and area under curve (AUC). The group of migraine was compared with the remaining headache patients (TTH and other headaches). The group of TTH was compared correspondingly with the patients with migraine and other headache.

Results

Four hundred and twelve children with chronic or recurrent headache were found in the epidemiological study – 132 of them with only migraine, 175 with only TTH and 89 with other headache.

Two hundred and three children with chronic or recurrent headache were found in the clinical study – 95 of them with only migraine, 60 with only TTH and 33 with other headache.

Headache characteristics and associated symptoms in both migraine and TTH

The pain characteristics and associated symptoms for migraine and TTH are presented in Figure 2.The most frequent quality of pain in migraine was pulsating (64.7%), whereas in TTH, it was unspecified (48.1%), followed by pressing-tightening (34.9%). The differences were highly significant (p < 0.001).

Figure 2.

 Frequency of symptoms in migraine (n = 235) and TTH (n = 232)

‘Severe’ was the most frequent pain intensity for migraine and significantly more common than in TTH (66.4% vs. 11.5%) (p < 0.001). Moderate intensity was common for both headache types, but prevailed in TTH (p < 0.01) (Figure 2). Mild intensity occured in higher percentage of children with TTH than with migraine (41.3% vs. 2.6%), p < 0.001.

Bilateral location was the prevailing location for both headache types, but it was significantly more common in TTH than in migraine (p < 0.001) (Figure 2). Bilateral location in migraine was mainly either bifrontal or bitemporal, whereas bilateral location other than bifrontotemporal was more frequently found in TTH.

Unilateral location was reported by less than a third of migrainous patients, but it was still significantly more common than in TTH patients (p < 0.001) (Figure 2).

Pain aggravation by routine physical activity occured mainly in migrainous patients (Figure 2) and the difference was highly significant (p < 0.001).

Amongst associated symptoms, phonophobia was the most frequent symptom for both headache types, but significantly more common in migraine (p < 0.001). Other symptoms as photophobia, nausea and vomiting occured rare in TTH in contrast with migraine (p < 0.001) (Figure 2).

Diagnostic item ‘photo- or phonophobia’ was established in higher percentage than the previous one ‘photo- and phonophobia’ in migraine (p < 0.001) (Figure 2).

Univariate analysis of clinical characteristics included in the diagnostic criteria for migraine and TTH

Univariate analysis of diagnostic items for migraine

The results of Se, Sp, OR and AUC of each tested characteristic of migraine are displayed in Table 1.

Table 1.   Evaluation of clinical characteristics of migraine (arranged in descending order according to AUC in univariate analysis)
Diagnostic itemSeSpAUCp-valueOR (95% CI)
  1. AUC, area under curve; OR, odds ratio; Se, sensitivity; Sp, specificity.

Moderate or severe intensity0.950.630.79< 0.00112.43 (7.12–21.7)
Nausea0.600.870.74< 0.00110.55 (7.01–15.87)
Pain aggravation by physical activity0.660.800.73< 0.0017.82 (5.37–11.38)
Severe intensity0.600.840.72< 0.0018.18 (5.55–12.06)
Photophobia0.610.840.72< 0.0018.16 (5.54–12.01)
Pulsating quality0.650.780.71< 0.0016.44 (4.46–9.29)
Photo- or phonophobia0.810.570.69< 0.0015.6 (3.81–8.25)
Photo- and phonophobia0.490.850.67< 0.0015.57 (3.77–8.23)
Phonophobia0.690.610.65< 0.0013.34 (2.35–4.73)
Vomiting0.330.960.64< 0.00111.94 (6.55–21.76)
Migrainous location0.760.450.61< 0.0012.63 (1.82–3.82)
Family history of migraine0.280.910.60< 0.0014.04 (2.54–6.41)
Unilateral location0.270.880.58< 0.0012.8 (1.8–4.35)
Vertigo/lightheadedness0.470.620.550.0251.47 (1.05–2.05)

The most sensitive item found in this analysis was moderate or severe intensity, followed by photo- or phonophobia and their Sp was above 50% (Table 1). On the other hand, the most specific characteristics were vomiting, family history of migraine, unilateral location and nausea. All of them, except nausea, showed low Se (Table 1).

The following clinical characteristics of migraine with good balance between Se and Sp, and AUC above 0.70 were: moderate or severe intensity or only severe intensity, nausea, pain aggravation by routine physical activity, photophobia and pulsating quality (Table 1).

Univariate analysis of diagnostic items for TTH

Evaluating separate symptoms of TTH the results for Se, Sp, OR and AUC are presented in descending order according to AUC in Table 2.

Table 2.   Evaluation of clinical characteristics of TTH (arranged in descending order according to AUC in univariate analysis)
Diagnostic itemSeSpAUCp-valueOR (95% CI)
  1. AUC, area under curve; OR, odds ratio; Se, sensitivity; Sp, specificity; TTH, tension type headache.

No photophobia0.940.550.74< 0.00119.14 (10.72–34.16)
No nausea0.960.490.73< 0.00122 (11.29–42.85)
No aggravation by routine physical activity0.890.560.72< 0.0019.89 (6.29–15.55)
Mild or moderate intensity0.910.520.71< 0.00110.58 (6.44–17.4)
Non-pulsating quality0.840.570.70< 0.0016.85 (4.54–10.33)
Mild intensity0.430.930.68< 0.0019.69 (5.93–15.83)
No phonophobia0.670.630.65< 0.0013.49 (2.47–4.94)
No vomiting0.990.250.62< 0.00125.2 (7.87–80.73)
Bilateral location0.950.270.61< 0.0016.92 (3.6–13.28)
Pressing or tightening quality0.350.860.61< 0.0013.38 (2.25–5.08)
No vertigo/lightheadedness0.660.470.560.0021.71 (1.22–2.41)

Most diagnostic items for TTH had high Se – no vomiting, no nausea, bilateral location, no photophobia – 99%, 96%, 95%, 94%, respectively, but bilateral location and no vomiting, had low Sp (Table 2).The most specific symptoms were mild intensity and pressing- tightening quality, but their Se was low (Table 2).

The clinical characteristics with good balance between Se and Sp, and AUC above 0.70, were: no photophobia, no nausea, no aggravation by physical activity, mild or moderate intensity, non-pulsating quality (Table 2).

Multivariate analysis of clinical characteristics as diagnostic items for migraine and TTH

The results of multivariate logistic regression analysis of the items included in the diagnostic criteria C and D for either migraine or TTH, and two more factors – vertigo/lightheadedness and family history of migraine, are presented in Figure 3 in descending order according to OR.

Figure 3.

 Diagnostic value of the clinical characteristics for migraine and TTH according to multivariate analyses

Pulsating pain was the item, which increased to the highest extent the migraine risk (seven-fold). It is followed by pain aggravation by physical activity, moderate or severe intensity and nausea. They increased the chance for migraine to a similar extent –five-fold. Phonophobia increased the migraine risk least (1.9-fold). Family history of migraine was also a significant item for increasing the migraine risk, more than phonophobia, whereas vertigo was not a significant item.

Among the diagnostic items for TTH no photophobia, bilateral location and no nausea increased TTH risk to the highest extent – approximately 14-fold. The next items according to their significance were no aggravation by physical activity and non-pulsating pain – they increased the risk for TTH to a similar extent – 8 1/2-fold. No family history of migraine was also a significant item, whereas no vertigo was not.

Discussion

This study evaluates the ICHD – II diagnostic criteria of the two most common primary headaches with reliable statistical parameters. The study is specific for children. The results are applicable in in- and outpatient paediatric practices.

Migraine

There are variable data and limited statistical evaluation of the characteristics of migraine in the literature (6,13,16,18,19,21,22,25,26,30,34,36).

According to our results, the main pain quality in migraine was pulsating, significantly more common than in TTH. Pulsating quality had 65% Se and high Sp – 78% and AUC – 0.71. This supported the use of this item as diagnostic for migraine. Most authors also established high Se of this pain quality (6,13,16,19,25,34,36,37). Pulsating pain was reported in higher percentage (78–96%) by adult population (21,38–40) and the lower occurrence of this symptom in paediatric population could be explained by a child’s difficulties in describing the pain quality.

Unilateral location had high Sp – 88%, but low Se – 27%. Low Se of this item in children and adolescents was also established in other studies (6,16,18,19,25,37), in contrast with higher Se (53–74%) in adults (21,38–40). That is why unilateral location was confirmed as diagnostic item in criterion C for migraine in adults in ICHD – II (23). Regardless of its lower Se in paediatric age, unilateral location occurred significantly more commonly in migraine than in TTH in children and adolescents, and unilateral location was considered specific for migraine. When combining unilateral, bifrontal and bitemporal location as diagnostic item ‘migrainous location’, the Se increased to 76%, the Sp was 45% and AUC was higher than the one of unilateral location. Therefore, the changed variant of location for paediatric age as either unilateral or bifrontal/bitemporal location was a more reliable diagnostic item and our results confirmed the new variant of location in criteria of ICHD– II (23).

Several authors described high Se and Sp of the item moderate or severe intensity for migraine (6,30,33). In contrast with them, Gherpieli et al. revealed low Sp of this item (34). Turkdogan et al. pointed out that moderate intensity was the prominent one for both headache types migraine and TTH (19). According to our results, severe intensity prevailed significantly than moderate intensity in migraine, and it was highly specific for migraine.

In our study, moderate or severe intensity had high Se – 95%, Sp – 63% and AUC – 0.79. When focusing only on severe intensity the Sp increased – 84%, whereas Se remained high – 60% and AUC was close to the one of moderate or severe intensity – 0.72. Considering these results and in accordance with Pajaron and Wober-Bingol et al., we could recommend changing the content of the item of intensity as only severe intensity (30,41). In this way, moderate intensity would not overlap in the diagnostic criteria for migraine and TTH.

Pain aggravation by routine physical activity occurs in high percentage (86–96%) of migrainous adults and is considered as typical symptom for migraine (21,39,40). The role of this item in migraine diagnosis in children is controversial (22,26,30,35,42). In our study, this symptom occured significantly more commonly in migraine than in TTH. It had high Se, high Sp and AUC – 0.73, which confirmed this item as a diagnostic one. Thus, our results supported the opinion of Kroner- Herwig et al. and Smetana et al., who considered it as an important differential factor in contrast with Rossi et al. and Seshia et al. (22,26,35,42).

All associated symptoms in migraine are reported in higher percentage in adult migrainous population (82–89% for nausea, photophobia, phonophobia vs. 60–68% in our patients and 47–50% for vomiting vs. 32% in ours) (21,38,39). The lower Se was the reason for changing the criterion of associated symptoms in ICHD-II, so that photo- and phonophobia was replaced by photo- and/or phonophobia and in this way criterion D is fulfiled when at least one of the four associated symptoms occurs.

According to our results, nausea and photophobia were the associated symptoms, which had the best balance between Se and Sp, AUC above 0.70. With such AUC nausea and photophobia were proved as the most reliable diagnostic items of associated symptoms for migraine. Nausea was pointed out as a symptom with good Se and Sp by Wober-Bingol et al. as well, and they considered it as an important differential diagnostic feature between migraine and TTH (30).

Turkdogan et al. revealed low percentage of children with only one of the two symptoms – photophobia and phonophobia and suggested this item to be returned in its previous variant – both symptoms to be required simultaneously (19).

In our study, the previous item photophobia and phonophobia had Se 49%, Sp – 85% and AUC – 0.67, whereas the new version – photophobia and/or phonophobia had higher Se – 81%, Sp – 57% and higher AUC – 0.69. Our results corresponded with the data from other authors and confirmed the new content of this item in ICHD – II – photophobia and/or phonophobia (16,33).

Vertigo or lightheadedness is not included in the accepted diagnostic criteria. We found it significantly more often in migrainous patients, than in TTH patients, similar to other authors (19,25). When using multivariate logistic regression analysis vertigo or lightheadedness was not a significant factor. These results support the rationale for continuing the discussion of vertigo as an additional symptom of migraine.

According to our results of AUC, the best diagnostic items of pain characteristics for migraine were moderate or severe intensity or only severe intensity, pain aggravation by routine physical activity and pulsating quality (AUC – above 0.70). Photophobia and nausea were the most reliable diagnostic items among associated symptoms according to AUC.

Using the multivariate logistic regression analysis, pulsating pain was the diagnostic item, which increased the migraine risk most -seven-fold. The next significant items were aggravation of the pain by routine physical activity, moderate or severe intensity and nausea (they increased the migraine risk five-fold). Family history of migraine also increased the migraine risk two-fold, which supported the suggestion of Seshia, this item to be an additional one in criterion C (35).

There is limited data in the literature evaluating the symptoms, included in the diagnostic criteria for migraine of ICHD-II by multivariate analysis. Karli et al. established that nausea was the most important factor for the diagnosis of migraine – it increased the risk five-fold (similar to our result), followed by vomiting (18). According to their results, pulsating pain came third – it increased migraine risk 3.5-fold, in comparison with our analysis, where pulsating quality was the most important factor (18). Ozge et al. reported that unilateral pain had the highest OR in their logistic regression analysis – 22.6 when they used the neurologist’s diagnosis as the gold standard (6). The next symptoms with high OR in their analysis were vomiting and pulsating quality (6).

TTH

There are even less studies, which evaluate the clinical characteristics of TTH in children and adolescents, compared with such about migraine (18–20,30).

Gallai et al. demonstrated that pressing-tightening quality, bilateral location and mild or moderate intensity of the headache had higher Se for TTH (73.8%, 75.7%, 87.4%, respectively) than the corresponding criteria for migraine, but their Sp was lower, especially for bilateral location (36).

In our study, the most sensitive items for TTH – no vomiting, bilateral location (Se at least 95%) had low Sp – less than 30%.

Mild intensity had the highest Sp, but it had low Se – 43%. Combining mild and moderate intensity, the Se increased – 91%, the Sp remained above 50–52% and AUC was larger than AUC of mild intensity. Thus, the content of this item – mild or moderate intensity was ascertained. Our results were similar to other data (18–20,43). Gallai et al. even considered that mild-to-moderate intensity should be an obligatory criterion for TTH (36).

The symptom pressing-tightening quality was considered as typical for TTH and Se of this symptom in several studies was above 50% (26,43), as in adults (52–78%) (39,44,45). According to our results, only the pain quality of headache characteristics and associated symptoms differed significantly in children and adults (pressing-tightening pain was more common in adult population) (39,44,45). In our study pressing-tightening quality had high Sp, but low Se – 35% and this result was in accordance to Ozge’s data (6). Many patients could not determine the quality of the pain, as well as Seshia et Wolstein’s patients of paediatric age (35). That’s why non – pulsating quality had high Se and Sp, AUC – 0.70 and this fact confirmed the content of this item as pressing-tightening (non-pulsating) quality.

The item no pain aggravation by routine physical activity had high Se and Sp above 50% and our results supported most of the existing data in the literature (19,26,30,43).

Among associated symptoms, the most frequent one was phonophobia and our results were similar to the Ozge’s results (6) and to studies in adult population (39,44,45). However, phonophobia occurred significantly more often in migraine than in TTH.

The items of pain characteristics with AUC above 0.70, which confirmed their significance as diagnostic items, were: no aggravation by physical activity, mild or moderate intensity, non-pulsating quality. Considering the associated symptoms, the best diagnostic items according to AUC were no photophobia and no nausea.

Multivariate logistic regression analysis of the clinical characteristics of TTH showed that no photophobia, bilateral location and no nausea were the most significant items – they increased the chance for TTH approximately to the same extent – 14-fold. The next significant items were no aggravation by physical activity and non-pulsating pain.

No family history of migraine in patients with headache also increased the TTH risk three-fold, whereas no vertigo was not a significant item. That is why the lack of family history of migraine could be recommended as additional item in differentiating migraine without aura and episodic TTH with overlapping diagnostic criteria.

Using multivariate logistic regression analysis, Karli et al. established that bilateral location was the most important item for TTH (it increased the TTH risk 3.5-fold) (18). The next significant item in their study was mild or moderate intensity (two-fold risk increase) (18). However, the authors, in contrast with us, included in the analysis, the occurrence of associated symptoms, not the lack of them and thus it was impossible to evaluate the significance of items included in the diagnostic criteria, such as no nausea, no vomiting, no photophobia and no phonophobia.

Conclusion

Regarding the AUC, the best diagnostic items of clinical characteristics for migraine are: moderate or severe intensity or only severe intensity, pain aggravation by physical activity, pulsating quality.The respective items for TTH are no photophobia, no nausea, no aggravation by physical activity, mild or moderate intensity, non-pulsating quality.

The recent changes in the criteria items location (unilateral or bifrontal/bitemporal) and photophobia and/or phonophobia in IHDC– II for migraine were more reliable diagnostic items than the previous ones.

AUC of severe intensity is close to the AUC of moderate or severe intensity and we could recommend changing the content of the item of intensity for migraine as only severe intensity, and thus we could avoid overlapping of this criterion in both headache types – migraine and TTH.

Using multivariate logistic regression analysis, the most significant symptoms for increasing the migraine risk were pulsating pain, followed by pain aggravation by physical activity, moderate-to-severe intensity and nausea. The most significant items for increased TTH risk were no photophobia, bilateral location and no nausea. Family history of migraine also increased migraine risk and no family history of migraine increased TTH risk. Therefore, family history of migraine could be either included in the diagnostic criteria for migraine or recommended as additional item in differentiating migraine without aura and episodic TTH with overlapping diagnostic criteria.

Author contributions

Iliyana Pacheva: Study design, Data collection, analyses and interpretation. Ivan Milanov: Data interpretation and approval of article. Ivan Ivanov: Data collection, critical revision and approval of article. Rumen Stefanov: Statistics and approval of article.

Appendix

Appendix 1: Definition and categorisation of headache characteristics:

Types of headache are classified according to the International Classification of Headache Disorders – II – 2004 year.

‘Mixed headache’ meant coexistence of episodes of TTH and migraine.

‘Overlapping headache’ covered cases, which could be classified as either probable MWA or probable ETTH.

‘Other headache’ included headaches different from only migraine, only TTH and secondary headache.

Localisation of headache was differentiated as unilateral, bifrontal, bitemporal, diffuse, occipital and other.

‘Migrainous location’ included unilateral, bifrontal or bitemporal location

Pain intensity was defined as mild, moderate, severe and different.

The quality of pain was differentiated as pulsating, pressing-tightening, stabbing, undetermined and different. Non-pulsating quality included all qualities different from pulsating.

The aggravation of pain by daily physical activity was coded as ‘yes’, ‘no’ or ‘sometimes’. ‘Yes’ and ‘sometimes’ were summarised as a positive answer.

Associated symptoms as nausea, vomiting, photophobia, phonophobia, vertigo/lightheadedness were coded separately as ‘yes’, ‘no’ or ‘sometimes’. ‘Yes’ and ‘sometimes’ were summarised as a positive answer.

Positive first or second line family history of migraine was noted as ‘yes’ or ‘no’.