This study reports the accuracy of diagnosis, grading, and treatment of COPD according to guidelines in daily practice. Despite the wide availability of local COPD guidelines , corresponding to international guidelines, this study suggests that primary care physicians’ clinical practice is often not in compliance with the current recommendations.
Fifty-eight percent of the patients were not referred for spirometry even though the necessity of spirometry in diagnosing, grading and treating COPD is well known. Research in various countries demonstrates that the extent of spirometry use in diagnosing COPD and grading frequently remains insufficient. Two studies conducted in the U.S. in the 2000s stated that only a third of the patients with newly diagnosed COPD had undergone a spirometry [9, 10]. Varying results are seen in Europe, from 30% in Italy and Spain, to 59% in Sweden [11,12,13,14].
Our study shows that despite the constant education efforts in Lithuania, recognizing and diagnosing COPD still remains a challenge. According to current data, spirometry use was reported for nearly half of the patients. These results look respectable in the context of the previously presented data. However, this might be due to the characteristics of the chosen primary care center as it is a large, well-equipped center situated in the capital city with convenient learning opportunities for family physicians. The aforementioned center provides an easy access to spirometry, other diagnostic tests, and consultants. It is possible that the situation might be worse in rural areas where various health care aspects are out of reach.
Spirometry continues to be underused despite its accessibility. As studies show , the availability of spirometry is not viewed as a barrier. The main reason for underuse of spirometry might be the lack of knowledge or resources which leads to difficulties in performing or interpreting the results. Even more importantly, these factors might contribute to cultivating a misconception that spirometry is not needed to diagnose COPD .
Study  suggests that the lack of recent training is not the main reason of insufficient use of spirometry. Lack of resources, such as insufficient time, complicated logistics and high expenses, further complicate adhering to guidelines. For example, in Lithuania the usual primary physicians’ consultation time for one patient is 10 to 20 min, excluding non-scheduled visits. The average consultation time of the primary care physician was reported to be 15 min and was shown to vary from 48 s in Bangladesh to 22.5 min in Sweden . Providers who felt limited by time and felt unable to integrate onsite spirometry into stream of patients were less likely to use spirometry to diagnose or assess COPD [18, 19].
Our study demonstrated that even if spirometry was performed, primary care physicians diagnosed COPD in 15% of patients that did not meet the spirometry diagnostic criteria. Other studies show variable degrees of misdiagnosis: from 10% [20, 21] up to over 40% of patients [22, 23]. Comparison of COPD diagnosis made in primary care against the diagnosis made in secondary care shows that primary care specialists who are not specialized in diagnosing COPD make mistakes more often than experts. In primary care, misdiagnosis of COPD may be attributed to the lack of awareness and knowledge of the disease which leads to the poor use of spirometry, as mentioned before [9,10,11,12,13,14]. Without the appropriate knowledge of the guidelines, physicians rely on clinical signs and anamnesis when diagnosing COPD.
Our study showed that primary care physicians confuse COPD with asthma and chronic bronchitis. In a multicenter US study approximately 40% of the patients who were previously diagnosed with asthma had COPD . This might be associated with the lack of knowledge in pulmonary diseases in general.
Multimorbidity is another factor of misdiagnosing COPD. Studies show that 38% of the heart failure patients are misclassified as having COPD . Furthermore, 25% of the patients with ischemic heart disease met the COPD criteria. Eighty-two percent of these patients were underdiagnosed . It seems that cardiovascular pathology can lead to both over and underdiagnosis of COPD. Although in literature comorbidities are associated with diagnostic inaccuracy,  in our study the number of comorbidities in patients with spirometry confirmed COPD and the spirometry unconfirmed group did not differ significantly.
In our study a quarter of patients’ grading was incorrect. In majority of the cases the mistake was the overestimating of the grade. Similar results are seen elsewhere. In 2014 a UK study compared the grading of airway obstruction in the primary and specialist care conditions. The proportion of patients whose grade of airway obstruction was misclassified, was significantly greater in primary care (43.4%) than specialist care (9.3%). The grade of airway obstruction found on spirometric assessment at specialist respiratory nurse-led clinic was different in 54.0% from that stated on the referral from primary practice . Inappropriate spirometry interpretation is one of the reasons for grade overestimating. Another reason might be that physicians evaluate pre-bronchodilator FEV1 instead of post-bronchodilator. A study on accuracy of diagnostic registers demonstrated that the severity grading of airflow obstruction based on pre-bronchodilator readings changed after bronchodilator in 18% of patients . One more potential reason for grade misclassification might be the confusion between obstruction severity grading and disease burden severity. Even in light of the new recommendations to tailor the treatment to the individual needs of the patient, the obstruction severity has to stay one of the factors to be accounted for among symptoms and exacerbation rate .
Inhaled bronchodilators are the cornerstone of COPD management and can increase exercise capacity and improve health status when used regularly. However, data about the treatment in our study showed that 70% of the patients were receiving appropriate treatments.
In a large study performed in the United Kingdom, results were quite similar to ours . The study demonstrated that for 59.8% patients with confirmed COPD inhaled medications were prescribed in line with 2009 GOLD guidelines. The overall guideline adherence to COPD treatment for population-based COPD cases has been reported significantly lower than amongst hospital-recruited COPD patients . However, more patients appeared to be overtreated for their GOLD grade than in our study, 37.7% versus 8%, respectively (over-prescribing of inhaled corticosteroids in COPD has been reported in a number of countries [13, 28, 31,32,33]. The fact that the frequent mistake is the abuse of steroids or long acting β2 agonists may be explained with the hypothesis that primary care physicians often start therapy after a relapse and subsequently maintain the same therapy without further investigations. Likewise, underlying factor may be the perceived similarity of COPD and asthma, the common occurrence of the two diseases together, and a hope that steroids could reduce the impact of symptoms in COPD. Also, it has been observed that age and comorbidities seemed to guide prescriptions for COPD medications more often than the assessment of dyspnea .
The consumption of long-acting bronchodilators in patients who had moderate or severe COPD was high (90%) in our study. Unlike the results in the US survey on COPD,  which reported that only 35% of primary care physicians chose a long-acting bronchodilator when a short-acting agent had failed. A third of physicians also chose a combination short-acting bronchodilator. In general, it has been reported that the proportion of patients prescribed with long-acting β2 agonists ranges between 23 and 56% in different practices,  and between 9 and 25% for long-acting anticholinergics in different practices . Surprisingly, even 4 (5%) patients who had moderate or severe COPD received no treatment at all.
Limitations and strengths
We are aware of limitations and shortcomings of our research. The study was conducted in a single center so it might not reflect the real diversity of patients, their care tactics and care limitations. Nonetheless, chosen primary care center was expected to demonstrate best possible results as it has good availability of needed facilities. Another weakness of our study is a small sample size which could reduce its ability to detect smaller significant differences. However, all current COPD patients of the center were included so the results should represent the population adequately. Lack of patient history such as smoking or smoking cessation and information about patients’ complaints is another weakness. Due to retrospective design of the study, some influencing factors could not be evaluated as they were not documented.